When a credit card in your Plan reaches a zero balance, Incredible will let you know and ask what you'd like to do with the money that was going to that card.
Your options
You'll have two choices:
Add to other cards - The amount that was going to the paid-off card gets redistributed to your remaining cards. This helps you pay them off faster without increasing your monthly payment.
Reduce your monthly payment - Your monthly collection is lowered by the amount that was going to the paid-off card. Your remaining cards keep the same allocations they had before.