You might be able to, but only if you call them, or better yet, find out an actual name of a person that handles customer service. A travel agent should be able to give you a name and number.

Last year I had accumulated about 16 of them. For me they are basically worthless since I live over an hour from a rental center and never travel on a weekend that is only 2-3 days. However, I used my contact number and was able to barter 16 of them for an 8 day rental in Hawaii.

I sure wish Avis would just give us free rental days..............