Obviously, the best answer is to contact a Real Estate Attorney to be sure that you do not have liability. There are a few good ones in the Great Falls area. Be sure that you contact one in the state that the property is in as Real Estate laws can vary from state to state.
Having worked in the mortgage industry, I can tell you that if your name is not on the deed, if you did not sign any of the loan documents, if your name is not on those 1098's at the end of the year, you likely do not have an obligation to that mortgage. Whoever signed their name to that loan is responsible. If you were Quit Claimed on to the Deed at closing or sometime after closing that gives you an ownership interest in the home. You can certainly give up that interest if you so choose but I believe both parties would have to sign the Quit Claim, again, consult an attorney or a local title company for guidance on those issues.
I am sure you have your own reasons for giving up an ownership interest in a home but remember, once you give up your interest, you may have no grounds to go back and collect a portion of the profit should the home ever be sold. Please consult with an attorney before making this decision so that you know all of your alternatives and the outcome of any alternative that you may choose.
Please feel free to call me if you need any further information. Have a great day!