Work Authorization vs Change Order: Which One Do You Need?
Both documents can capture approval, but they solve different moments in the job. Here is a practical way to decide what belongs in front of the customer.
A work authorization and a change order can look similar because both may describe work, price and approval. The distinction is usually about what existing agreement you are relying on and what the customer is authorizing at that moment.
| Work authorization | Change order | Completion sign-off | |
|---|---|---|---|
| Best used | Before diagnostic/service work or a defined task begins | When an existing contract's scope, price or time changes | When the work is finished or handed over |
| Core question | “May we perform this work?” | “Do we agree to modify the existing job?” | “Do we acknowledge what was completed?” |
| Typical content | Requested work, authorization limit, service conditions | Changed scope, cost adjustment, schedule impact | Completed scope, remaining items, handover acknowledgement |
| Timing | Before work starts | Before changed/extra work proceeds when practicable | At closeout or milestone completion |
Use a work authorization when the customer is authorizing the work itself
This is common in service businesses. A technician arrives to diagnose a problem; the customer authorizes troubleshooting up to a stated limit. A property manager authorizes access and a defined repair. An emergency plumbing call requires permission to open a wall or replace a failed component.
A useful work authorization should identify the customer and location, describe the requested/authorized scope, state any spending or estimate limit, mention material or access assumptions where relevant, and include the acknowledgement that the customer is authorizing that work.
Use a change order when an existing agreement is changing
A change order is anchored to an existing contract, proposal or accepted estimate. The job already exists; now one or more of its terms are changing. The practical record should connect the original agreement to the revised scope, price and time impact.
If the original estimate was $8,000 and the customer adds a $1,200 upgrade, that is a different recordkeeping problem from authorizing an initial diagnostic visit. The change order should make the $1,200 modification understandable in the context of the original job.
Use a completion sign-off when the question is whether the job is finished
Completion sign-off is about closeout: what was delivered, what remains, what was handed over and what the customer acknowledges at that point. It can be useful before issuing a final invoice, releasing a crew from site, transferring warranty information or documenting a punch list.
Sometimes you need more than one
A well-run job can legitimately use all three. A customer signs a work authorization for the initial service. During the job, a concealed condition creates additional work and a change order is approved. At the end, the customer signs a completion acknowledgement that lists completed scope and any remaining items.
What should you sign electronically?
Electronic signing is most useful when the recipient needs to approve a specific, stable version of the document. Send the PDF that actually contains the scope, price or closeout terms; avoid asking someone to “approve the email” while the real terms live somewhere else.
Quick decision tree
- Is there already an accepted contract/estimate? If no, a work authorization or proposal acceptance may fit better.
- Are you changing existing scope, price or time? If yes, use a change order or the change process required by your contract.
- Is the work already finished? Use a completion sign-off/acknowledgement for closeout.
- Does your contract require a particular form or approval path? Follow it. A generic form should not override negotiated contract requirements.