If you want to use your ID card, you need someone to sign the deposit at last, but you don't have to sign it yourself.

Might as well not return it. You can change it to Class A, so you can continue to use it after the deposit is refunded, but you can borrow it but you can't lend it out.

Anyway, even if you refund the fee of 15, you won't return the card. It's more cost-effective to change it.