Paul, a plumber, agrees to install a shower stall in Harry's home for a fee of $500. After entering into the contract, Paul subcontracts the work to Pauline, a licensed plumber who agrees to do the work for Paul for $400. When Harry learns of the delegation of contract duties by Paul, he is furious and wants to invalidate the contract. What result? If Harry accepts performance by Pauline but is unsatisfied by the work she performed, who can he sue for damages?