Yes, this is very easy to do. Call up Bank one number on back of Creditcard and go through prompts. If you have more than $20 reward $$ then they will send you a rewards card in the mail (they ask that you call them at least 3 weeks prior to your vacation date). After getting your card, you can call the number again and have more reward $$ moved to it as long as you have $10 more rewards dollars earned by the time you call. I know this as I just ordered mine a few days ago. My trip is about 3 weeks away and I had to ask a few questions as I purchaed a lot on my card this month (in prep for upcoming vacation, tickets, food vouchers, etc.). As my billing cycle will end at the end of this month, I wouldn't have enough time to get all rewards on card before leaving so I am having $60 put on the card and will call them shortly before leaving to have the rest (over $10) placed on the card.
I also recently asked this question here as well and one poster noted that you can go to DTD Guest Services and have the rewards card issued there immediately. I decided not to do this as I am not really sure what day of my trip I'll be making it to DTD (more than likely, one of the latter days I'll be at DTD but getting the card 2 or 3 days before the end of my trip won't help me to pay for those meals at the beginning of the trip which is what I am using it for). I do not know if you can go to any other Guest Services to get the card (I began to ask but got sidetracked by the other info. she provided me.) Hope this helps.