I've got a tenant who's moved out but the co-tenant has agreed to stay on and take over the lease. I'm OK with this since he makes enough to cover the entire rent. Can I simply write up a short addendum that says I'm removing the name of the tenant who has moved out? Do both parties have to sign or just the one who is staying on?

When does the lease expire?

The lease doesn't expire until Jan. 31, 2010.

OK, in that case I would do an addendum. You could offer the staying tenant a new lease extending the term

It is always fun when I disagree slightly with Scott.

1. what was your agreement with the one moving out, the one staying is already obligated, it is merely the one staying and you giving permission to the other person to move.

I think for myself, I would merely do a new lease ( but just for the number of months till that one expired)