How to evict 1 person on lease while letting other stay

[Mark Langdon]

I have 2 people staying together who are both on a lease. The one person pays all the rent from what I understand and she is trying to get rid of I think an old boyfriend that is not working out. Both her and him are on the lease together on a month to month lease. He is refusing to go because he doesn't have anywhere to go and he may be a deadbeat but not sure. She wants him out of there ASAP but she wants to stay. I know I shouldn't get in the middle of this because the rent gets paid etc. but wondering the best way to remove him while still letting her stay. She probably doesn't want to give notice and go thru the hassle of packing up all her stuff (she has kids) just to then move back in; but even with that he may not leave and be the only one left and then I have to evict him on my own.  She wants to know if I can just write up a new lease with just her on it and then she can get rid of him but I would think he would have to sign something saying its OK to terminate the lease. This is in NJ and I know I should consult my attorney and mostly likely will have to but trying to get any ideas before I need to start that.