James had a contract with frasier to fix a plumbing issue at frasier's home. the contract was made for $3,000. after the work was completed, frasier then refused to pay anything unless james agreed to accept $2,500. james's attempt to make a new contract is void because it lacks consideration under the concept.

pre-existing duty

Explanation:

Based on the information provided within the question it can be said that this lacks consideration under the pre-existing duty concept. This concept states that completion of the requirements agreed upon in a contract does not allow for valid changes within the contract. Which is what James is trying to do by changing the terms of the agreement after Frasier finished abiding to his part of the contract.

acid rain is the answer