Can i change the expiration date or do i need to remove the card and add it back

I have never had to change an Apple Pay expiration date. They have always updated automatically. If you do need to change it see the following from Manage the cards that you use with Apple Pay - Apple Support

While you can't change your card number or expiration date, it should update automatically when you get a new card. If your issuer doesn't support updates, you might need to remove the card, then add it again.