1. Sign in here: http://plus.ultimate-guitar.com/tab-pro/
2. Open your account page: http://plus.ultimate-guitar.com/account/
3. Go to manage your account.
4. Scroll down the page and click on the "Update payment details" button.
5. Choose the Credit card as a payment method:
6. Enter your new Credit card info:
7. Click on the "Complete" button.
If you see the following screen after step 2. click on the "Change" button and perform steps 5-7.