Remove name from a loan

I co-singned on loan for my mothers house about 7 years ago, and only lived there for about a year. I have never had to make a payment, my mothers salary was enough to do it. Since then, I have married, and moved out of state. My wife and I are looking to by a house, but I have this loan on my credit. My mom was late on the payments about 2 years ago, but caught up and was ok. Now, she is back in the hole, and is facing foreclosure. She wants to try to sell the house in the next year or so, and has contacted the bank about trying to removed my name form it. They told a simple assumption would do it, but I haven't been able to find an answer to if that would work. Is this the right way to do this, or is there another way to remove me from the loan and removed from my credit? Thanks