Do I allow my tenant to take her ex-boyfriend off the lease?

[Bryant K.]

I have a tenant that signed a lease in April with her boyfriend. She also had her mother cosign for her. The boyfriend and her have broken up but he still stays there every once and awhile when he's visiting with or watching their daughter when she works nights. She's requestes to have him removed from the lease because their relationship is over.

What are your thoughts on how to handle the situation? When couples break up do allow one person to take over the lease or do you deny the request since he took on the responsibility of being liable for rent for the year?

Lets say she starts dating someone new and moves in a new boyfriend next month. At what appoint and how do you handle adding someone new to the lease? What documentation do you have the new spouse submit?