Attach Number to Reservation?
 

I rented a car from Avis via Priceline and want to attach my account number to that reservation? I'm hoping to get the presidental plus upgrade (from continental). Is this something that can be done? Or will I need to use my card at the location when I pick it up.

You most likely won't be able to reap the benefits of any association on a pre-paid third party rental. They generally aren't eligible for any upgrades/miles/points, etc. because the rate is so low to begin with.

Avis won't attach the # on a PL booking, your strategy is either to call the location directly in advance or more likely just to show up with card in hand.