Debtor's $1,000 contractual obligation to Aunt was due on July 1. On the preceding June 15, Aunt called Niece and said, "As my birthday gift to you, you may collect on July 1 the $1,000 Debtor owes me." Aunt also called Debtor and told him to pay the $1,000 to Niece on July 1. On July 1, Debtor, saying that he did not like Niece and wouldn't pay anything to her, paid the $1,000 to Aunt, who accepted it without objection. Will Niece succeed in an action for $1,000 against Debtor? 
Yes, because Aunt had effectively assigned the $1,000 debt to her.  Yes, because Aunt's calls to Niece and Debtor effected a novation.  No, because Aunt's acceptance of the $1,000, without objection, was in effect the revocation of a gratuitous assignment.  No, because Debtor cannot be compelled to render performance to an assignee whom he finds personally objectionable. 