Well, this depends on where you made the transaction, so you have the following options: 

❶⠀Prin BT24 app if you made the transaction online. On the plus side, you have 2 options here too: 

➤⠀if you come to the counter in any BT unit;

➤⠀modify directly via BT24 secure messaging* where you must request this in writing.

❷⠀In the BT unit where you made the transaction, filling in a request with the new details.

* BT24 secure messaging, can be found in the application as follows:

➤⠀Mobile ➭ "Messages " menu ➭ "Ask BT" section;

➤⠀On your PC ➭ at "Mailbox" (it's on the right side of the screen).