You bet you do! As others have said, you MUST address your concerns to an attorney. If you have less than three properties in this status, making changes should be relatively easy. If you own more than three......your really, reallly, really, really, need to do what ever you must to provide incentive for your renter/buyer to enter into another agreement. If THEY consult an attorney, and you have more than three.....you will be fastened using a tapered shaft with a helical thread. Call the attorney you used to draw up the original agreement.