Your video subscribers can change their payment details at any time, though the method of doing this will be different depending on the Payment Gateway you have chosen.
For Stripe Users:
If you are using Stripe as your payment gateway, your customers will be able to change their payment details right from within their customer dashboard.
All they need to do is Log in to their dashboard, find their current subscription, and click the "Change Payment" button.
A window will appear asking your customer to enter their new credit card information. Once they have entered it, they just need to click "Submit"
For PayPal Users:
If you are using PayPal as your payment gateway, your customers will need to change their subscription payment details within their PayPal account. Have them follow the instructions in the link below.