Well, you actually have 2 scenarios you can find yourself in:

1. if you want to change the IBAN account associated with the Alias Pay service, you can restart the RoPay Alias enrollment process and choose a different BT current account. This will overwrite the information originally saved.

2. if you want to change your phone number, you need to delete the Alias you originally set and re-start the Alias Pay enrollment process.3 move your RoPay Alias to BT if it is active with another bank. You can only have one RoPay Alias.