BI4IKE
Okay, I understand. Based on the previous logic, it's like this:
I have sent a request to reverse the card, and once you agree, only the recipient will be able to see your address information. This is indicated with a prompt when confirming.

Later, I will consider further optimization to allow both parties to view each other's address information.
However, from what I can see currently, there shouldn't be any major problems. The person initiating the card exchange should first send the card.
Once you agree on your side, the other party will also receive a notification.