Ellen Elderly was an 80 year old woman who employed Doris Disaster as her caregiver for 8 hours per day. Each Day, Doris would ask Ellen to change her will to leave her house, valued at over $1 million, to Doris because Doris was so good to her as her caregiver and because Ellen's children totally ignored Ellen except around Christmas time when Ellen gave each of them a check for $250. Doris continued to ask Ellen to change her will every day for over a year. Finally, Ellen agreed to leave Doris the house. She wrote a note that said, "This note will serve to change my will. Because Doris Disaster has been such a wonderful caregiver, and because my rotten kids did not visit me enough, I am leaving my house and all of its contents to Doris Disaster." Ellen signed and dated the note and gave it to Doris. After Ellen's death, Doris gave the note to the executor of Ellen's estate. The executor treated the note as an amendment (change) to Ellen's will. Ellen's children sued Doris to invalidate the note. What cause of action would Ellen's children bring to invalidate the note and what remedy would Ellen's children be seeking?