The mezzanine is half bolted down, the customer has just asked for another forty feet of guard rail, and your installer is standing there waiting for an answer. You want a number out today, and you do not want a three-week argument in October about what the purchase order actually covered.
Most change order fights are not about money. They are about two people holding different ideas of what the accepted order included, and nobody writing the difference down before the work happened.
Three buckets, never one
Every mid-job request from a customer falls into one of three buckets, and the whole job is sorting them before you price anything.
- Genuinely extra. Not on the drawing, not in the scope, not in the quantities you priced. This is billable.
- Already included. It is in the scope or the bill of materials, the customer has forgotten or is reading the revision differently. This is a clarification, not a change order, and it costs nothing.
- Your own correction. Damage in transit, a part fabricated to the wrong length, a missed hole pattern. This is rework you owe, and it is never billable.
The fight starts when all three arrive in the same phone call and you answer with one number. Split them, name each one, and the conversation changes shape.
The method, step by step
- Write the accepted baseline down first. Before you look at the new request, get the agreed scope into one place: the PO number, the revision of the drawing or spec you quoted against, the line quantities, the delivery date, and anything the customer asked for that you priced out and excluded. If that record lives across eight emails and a marked-up PDF, the job brief builder will pull it into a single brief with a clean line between what is agreed and what was only asked for. You cannot classify a change without a baseline to classify it against.
- Classify each item on its own line. One request often hides three items. Take them one at a time and put each in a bucket. If an item is arguable, say so out loud in your own notes rather than quietly pricing it as extra. Arguable items are where credibility gets spent.
- Strip out anything you owe. Rework caused by your shipping, your fabrication or your install crew comes off the sheet before costing begins. Not discounted, not folded in quietly. Removed, and then mentioned in the document at no charge so the customer can see you handled it. This is the single cheapest way to make the billable part of the same message land without resistance.
- Cost the increment only. The question is not what forty feet of guard rail costs. It is what forty feet of guard rail costs on top of the job you are already doing. Count the incremental hours (fabrication, paint, install), the incremental material at today's supplier price rather than the price you quoted in June, incremental freight, and any re-delivery or second mobilization the change forces. Then check for what does not increase: if the crane is on site anyway, the customer is not paying for the crane again. If the truck is going back regardless to fix something you owe, the customer is not paying for the whole trip.
- Price it, then keep the composition to yourself. Work out your cost, apply your normal markup, and put a single price on the line. The customer's draft shows scope, price and effect on the schedule. It does not show your hourly rate, your material cost, your markup, or a line called overhead recovery. A costed sheet invites the customer to negotiate each component. A scoped price invites a yes or no. The pricing and margin check is where the breakdown belongs, for your eyes, before you commit to the number.
- State the schedule effect separately. Price and date are two decisions. Mix them and the customer approves the price while assuming the original completion date still stands. Write one line: what the change does to the finish date, and whether that date holds if approval arrives by a stated day. A change approved four days late is a different change.
- Get written approval before the work. Not "the site manager nodded". Approval means one of these: a reply to your change order email saying yes or approved, a signed copy of the change order, or a revised purchase order carrying the new line and value. Anything else is a conversation you will be asked to prove later. Send the request, name the day you need it by, and hold the work. The change order approval skill will draft the request and put the approval line in it.
- Log it against the PO. One reference, one date, one value, filed with the original order. When the invoice goes out and somebody in accounts payable queries the total, the answer is a document, not a memory.
The prompt
Paste this into ChatGPT with the original PO or quote and the customer's message. Change the details to your own job.
Here is the purchase order we accepted, and underneath it the email our customer sent this morning asking for extra work. Go through the customer's request item by item. For each item tell me whether it is genuinely extra to the accepted scope, already included in what we quoted, or our own mistake that we should fix at no charge. Then for the extra items only, list the incremental costs I need to price: labor hours by trade, material, freight, and any second delivery. Ask me for the rates and material prices, do not guess them. Then write a short change order email to the customer with the scope, one total price, the effect on the completion date stated separately, and a line asking for written approval or a revised PO before we do the work. Do not put my costs, rates or markup in the customer email.
A worked example
The figures below are an illustration, not a real job.
Hartwell Storage Systems is supplying and installing a steel mezzanine for Cortland Foods. The accepted purchase order, PO 41982, is $48,600 net 30: platform, stairs, 120 feet of guard rail to drawing revision B, delivered and installed over four days.
On day two the warehouse manager emails two things. He wants another forty feet of guard rail along the east edge, which is not on revision B. He also reports that one upright arrived from the truck bent.
Classification. The forty feet of rail is genuinely extra. The bent upright is Hartwell's own correction, damaged in transit on Hartwell's vehicle, and comes off the sheet.
Incremental cost of the rail.
- Rail section and posts, 40 ft at today's mill price: $1,040
- Five posts, base plates and fasteners: $325
- Fabrication and paint, 3 hours at $65: $195
- Install, two fitters for 3 hours at $78: $468
- Re-delivery of the rail sections: $310, but the truck is already going back to Cortland with the replacement upright, so only half the run is chargeable: $155
Incremental cost: $2,183. At Hartwell's normal markup on fabricated and installed work, the price on the customer's draft is a single line: 40 ft additional guard rail, east edge, supplied, delivered and installed: $2,950.
What the customer sees. One scope line, one price, then two separate statements. First: the bent upright is being replaced at no charge and the replacement is on the same truck. Second: the change adds one day to the install, and the revised completion date holds only if written approval or a revised PO reaches Hartwell by Thursday.
Nowhere in that message is a rate, an hour or a markup. The customer has one decision to make, and the thing that would have caused the argument in October, the bent upright, has already been answered in the same breath.
What to check before you send
- The revision number you are quoting against is the one the customer holds. Changes against the wrong revision are how a clarification becomes a claim.
- Material prices are today's, not the ones in the original quote.
- Nothing you owe has crept into the billable lines, including freight you would have paid anyway.
- No hourly rates, material costs or markup appear anywhere in the customer draft.
- The schedule sentence is separate from the price sentence, with a date the approval has to arrive by.
- The approval line names what counts: an email reply, a signature, or a revised PO.
- The PO number and your change order reference are both on the document.
Close
A change order is not a negotiation, it is a record. Sort the request into extra, included and yours, price only the increment, hold the work until the approval is in writing, and the fight you were expecting mostly does not happen. If the change alters payment terms or you are looking at a disputed claim rather than a straightforward addition, put it in front of your accountant or attorney before you send anything.