When a party takes on a contractual obligation, they are legally required to perform the obligation.

That same contracting party is still entitled to subcontract out the work to another service provider, unless the contract:

- is a contract for personal services, such an employment contract

- contains an express term preventing subcontracting out the work, or an implied term

Subcontracting clauses are written to control whether the contractor is entitled to subcontract, and how purchaser shall control that subcontracting process.