If you need to replace your ID card, visit Wildcat Central in the Campus Center. They will be able to deactivate your lost card in their system so that no one else can use it.
You can request a new ID card at this link, this will allow you to just pick up your new card without waiting for it to be printed.
When a new card is printed, your old card will be deactivated. Even if you later locate your old ID, only this new card will work across campus.