If you leave the Church should you be re-baptized?
No, a validly baptized person should never be rebaptized under any condition.
Can. 845 §1 Because they imprint a character, the sacraments of baptism, confirmation and order cannot be repeated.
Baptism imprints an indelible mark upon the soul of the person who receives it. Once someone is baptized they are forever a baptized person. It is similar to being born into a family. Once you are born into the family you are forever a member of that family. You can physically not be around your family, but you are still genetically linked to the family you were born into.