Final answer:
The term for replacing a five-year contract with a ten-year contract after two years is often 'renewing,' 'extending,' or 'superseding' the contract, involving renegotiations and various implications.
Step-by-step explanation:
The action of replacing a five-year contract with a new ten-year contract after two years have passed is typically referred to as 'renewing' or 'extending' a contract.
In some cases, if the new contract entirely replaces the old one before its original expiration date, it may be considered 'superseding' the original contract.
This action may involve renegotiating terms and may have legal and financial implications depending on the original contract's conditions and the new agreement.