I want to go at this in a slightly different, but related way. I'm looking at getting a card that as a $120/year rebate for Avis rentals. However, it is not Primary coverage like my Sapphire. So, I'd want to book the car with the Sapphire for the coverage.
Then, assuming nothing happens to the car, I'd want to change to the other card upon return for actual payment. I'd only need to do this once a year for the rebate, so maybe the hassle is worth it once. Question is whether this would be allowed at return.
Cheers.
I have been asked if it’s fine to proceed to be charged with the card on file once so I assume you can change it on return. But the car rental company can charge you for damages found after the return and changing the credit card after return may void your credit card CDW.