Reassign – this legal term literally means to transfer an asset, goods or a right. In the area of Law of Contracts, reassignment is the act via which the assigned contractor (the one who has to perform something) transfers his obligations to other, sub-contractor. In other words, he reassigns the job. But usually he is still obliged to the assignor for any wrongful actions, done by the sub-contractor.
In practice, parties usually agree in their contracts that eventual reassignment won’t bring escape of liability by the contracting party.