"Can I keep the car until Sunday?" It is one of the most frequent requests at the counter, and one of the worst handled. Many agencies say yes on the phone, take an extra payment, and never touch the contract. The day a dispute arises, the signed document describes a period that no longer matches the real rental.
This article describes the clean way to handle an extension, and what LocaFlotte actually does when you create an amendment.
Check first, promise afterwards
An extension is not only a matter of price: it is first a matter of availability. The vehicle may already be promised to another customer the day after the original end date. Before saying yes, you have to look at the vehicle's schedule over the new period.
LocaFlotte checks that availability again when the amendment is created: if another contract, in progress or signed, overlaps the new period on the same vehicle, the operation is refused. This is a server-side guardrail, not a simple interface message: it applies even if the reservation was confirmed earlier.
If the vehicle is not free, the extension becomes a vehicle change, which is another conversation — and another check.
What an amendment is in the product
An amendment does not overwrite the previous contract: it creates a new version, which becomes the contract in force and keeps the link to the one it replaces. At any moment, a single contract is "current" for a given reservation. That invariant is what lets you answer without hesitation the question "which document prevails?".
The amendment also carries a reason. "Three-day extension at the customer's request" is a sentence that, six months later, is worth more than a contract modified without explanation. The security deposit amount can be adjusted on that occasion if the new duration justifies it.
Modify, or issue an amendment?
| Contract status | What to do | Why |
|---|---|---|
| Still a draft | Modify it directly | Nothing has been signed or handed over: one more version would add no information. |
| Signed or in progress | Create an amendment | The customer holds a document; the new version must be traceable and attached to the old one. |
| Completed or cancelled | Leave it alone | A closed rental is corrected with a new file, not by rewriting history. |
The product enforces this rule: asking for an amendment on a contract that is still a draft is refused, with a message inviting you to modify it directly.
The new document has to be signed too
An amendment arrives as a draft. It becomes binding in the same way as the original contract: it is issued as a PDF, read through with the customer, then signed — at the counter, through a link sent to the customer, or through a link with a code received by email.
This is where many agencies stop too early. An amendment prepared but never signed is no better than a verbal agreement: it only shows that someone intended to do things properly.
Also read:Signing a rental contract, mode by modeGenerating a rental contract as a PDF
And the extra payment?
The extension changes the duration, therefore the amount. The extra payment is handled like any other payment on the file: amount, date, method, and a status saying whether it has actually been collected. As long as it has not, the outstanding balance shows it.
The classic mistake is to take the extra payment in cash without recording anything, because "the contract is already done". The file then looks settled when it is not, or the other way round.
Also read:Tracking cash payments, deposits and security depositsCar rental contract software
Frequently asked questions
Does the customer have to sign again for an extension?
Yes. The amendment is a new document: it is issued, read through and signed like the original contract. An unsigned amendment protects nobody.
What happens to the original contract?
It is kept. The amendment becomes the version in force and keeps the link to the one it replaces, so the full history of the file stays readable.
Can I extend if the vehicle is already booked afterwards?
No. Availability is checked again when the amendment is created, and the operation is refused if another contract overlaps the new period on the same vehicle.
Can the security deposit change in an amendment?
Yes. The amount can be adjusted on that occasion; otherwise the previous contract's amount is carried over.
My contract is still a draft, do I need an amendment?
No. As long as nothing is signed, modify the draft directly — the product refuses to create an amendment in that case.
See an amendment end to end
We start from a signed contract, extend the period and have it signed again, on a demonstration file.
Request a demonstration