my sister drew up a new will and had my mom sign? My mom didnt want that how do i go about changing the will back to the orginal?

One key issue is whether your mother had the legal capacity to make a Will at the time she executed her last Will, and whether she still has legal capacity.  In general capacity means that she knew that she was making a Will, she knew what property she owned and what property would pass through the Will, she knew who would normally inherit from her estate, and she knew who she wanted to Will the property to.  If it is proven that your mother did not have capacity at the time she executed the last Will, then the Will may be found to be invalid.  If your mother did have capacity when she executed the last Will, and if she still has has capacity, then she can execute a new Will and revoke the prior will. Another issue is whether undue influence was used to convince your mother to sign the last Will.  If it can be proven that your mother was subject to undue influence, so that her true wishes are not expressed by the last Will she signed, then the Will may be found to be invalid. Determining whether your mother had or has capacity, and whether was undue influence was used to get her to execute the Will can be a complex process. I strongly suggest that you contact a lawyer to help you determine your options.