Can I use a promotion card to pay for another person's wireless bill?

I heard that I can use an Att promotion card to pay for a wireless bill.
Unfortunately, because I am a mere member of a family account, I cannot pay for the bill by myself.
In this case, can I inform my account holder of the number of the promotion card, and let him to pay a wiress bill using the card number?
 
Thanks,
Hyemin