OK - not sure if this is your question, but here goes:
Back in the early part of this year, I called Chase for a new REWARDS card and asked that my current balance of rewards points at the time (about $150) be added to it for our trip to DLR in April. In April we used ALL of the points on the card, all the way down to zero.
The card itself (basically looks like a credit card) has remained in my wallet since, with 0 balance. I just called a few weeks ago and added my latest rewards points balance to the SAME CARD (the person you speak with will verify the number of the rewards card that they are applying the balance to). I just used all these points toward buying
MVMCP tickets for an upcoming trip, my card, again has ZERO balance. Before we go on this trip in December, I am guessing I'll have $15 - $20 more rewards points available, I will call just before our trip and apply these points to the same card, and then use it on our trip for a CS meal.
The REWARDS card I have has an expiration date, end of next year I believe. I will continue using this same card and just re-applying any current balance I have to the card, as I need them - UNTIL it expires. After it expires, I will call and request a NEW rewards card. Same thing if I happen to lose it, I would just call and ask for a NEW rewards card and then transfer my current points to this new card.
Hope this answers your question.