Same issue at some National locations (ones without Aisle). They pre-run contracts hours before projected arrival then simply "attach" a car to the contract when the customer arrives.

So once that happens you cannot cancel the reservation as the contract has been drawn up and is waiting for a car to be assigned to it.

Usually with Avis this only happens ~1 hour before your reservation time.

One way to avoid this with Avis is to set your arrival time "later" than you expect to arrive. For instance you plan to arrive at 5 PM (meaning Avis draws up your contract sometime around 4 PM) but you aren't sure if you will get the rental or not, so you instead put your arrival at 8 PM which gives you until 7 PM to cancel on your own.


But then if you actually go through with the reservation and go there at 5 PM you end up having a less efficient experience..

In the old days you could call your local Avis station to cancel... but it doesn't seem easy to call a local Avis station anymore.