Cards are independent of the account, in that it is possible to have a joint account without any card(s).
It is possible to get one card cancelled and leave the joint account unaffected. It may also be possible to get one card replaced from supporting Laser, to one supporting just ATM withdrawals. That may depend on your bank.
If the account is repayable to either, it is possible to get it changed so that both signatures are required on withdrawals, but that could preclude any card being active on the account.