N.Y.C. Admin. Code § 6-102: § 6-102 Performance of contracts.

a. Each agency shall require and enforce the faithful performance of every contract made by it.

b. If the contractor or contractors shall fail in any respect to fulfill the contract within the time limited for its performance, then the agency in charge thereof shall complete the same in the manner provided for in the contract. The cost of such completion shall be a charge against such delinquent contractor or contractors.

c. If any work shall be abandoned by any contractor, the appropriate agency, if the best interest of the city be thereby served, and subject to the approval of the board of estimate, may adopt all subcontracts made by such contractor for such work. All subcontractors shall be bound by such adoption. The agency shall readvertise and relet the work specified in the original contract, exclusive of so much thereof as shall be provided for in the subcontracts so adopted.