What legal concept involves replacing an old contract with a new one to relieve parties of liability?

Novation is the correct choice because it specifically refers to the legal concept where an old contract is replaced by a new one, effectively relieving the original parties of their obligations and liabilities under the initial agreement. This creates a fresh contract where a new party may be involved or where the terms may be altered entirely, but the critical point is the discharge of the original contract.

In contrast, termination simply ends a contract without creating a new obligation. An amendment involves making changes to the existing contract while keeping the original contract in effect. Voidance indicates that a contract is rendered void or unenforceable due to certain conditions, but it does not entail the substitution of a new contract. Thus, novation is distinct in its ability to both create a new contractual relationship and relieve previous liabilities, which is essential in many business transactions or legal agreements.