@proplady It's rare for a credit card company to allow you to use another credit card to make a payment. Here is Synchrony's policy:
What methods of payment can I use to pay my bill?
In addition to online payments (single, multiple and Autopay), we accept checks drawn on US financial institutions, money orders, Western Union, Walmart Bill Pay services or electronically submitted payments from your financial institution. Payments may also be made over the phone, but we will charge you a fee to make phone payments. Gift certificates and credit cards are not accepted as a form of payment.