Task: Story Composition
Input (English): Premise: Joe wanted to go to see his friend. 
 Initial Context: Unfortunately, he had already promised his mum he'd help her shopping. 
 Original Ending: Joe then told his sister, Sally, that his mum wanted help shopping. Their mum then decided to take both of them along. Joe learned that he would have been better off just going alone. 
 New ending: Joe then told his mum that Sally wanted help shopping. Their mum then decided to take both of them along. Joe learned that he would have been better off just going alone. 
Output (English): Unfortunately, he had already promised his sister Sally he'd help her shopping.