I have a VX credit that is set to expire next month.

Can I buy a nonrefundable and/or refundable ticket to "extend" the expiration of the credit?

I'm thinking of buying a ticket for a potential trip to vegas in the future but was wondering if i can change the flights when purchased with a credit. (i know for southwest all credits and flights must be taken before the expiration date, but the VX credit says i don't have to fly by the expiration date, just ticket)