I made a rental car (pay later) booking at Hertz via Expedia. I then called up Hertz and got them to add it to my Hertz account (I'm President's Club).

I needed to make a minor change to the booking (basically pickup later the same day at the same location), but Expedia wouldn't allow me to make the change. So, I made the change directly on Hertz's site.

My question -- is this likely to cause an issue when I pick up the car? Or conversely, if I decide to cancel, should I cancel on the Hertz site or on the Expedia site?

I would guess that Hertz is the definitive source of car info, so I shouldn't have a problem, but just wanted to recheck.

[And I just noticed that the reservation number seemed to change when I made an online change directly at Hertz, even though I didn't receive an explicit cancellation notice for the old reservation]