You may wish to undo a cancellation made to a clients contract. Unfortunately, this is not possible in the system, once a contract is canceled it is irreversible. In order to reestablish the contract, you would have to re-assign the relevant membership.
Our system unfortunately does not allow you to undo a cancellation. When a contract is canceled, and the end date has not yet been reached, you can move the end date further up in the future, but the contract will keep the status "canceled." A stopped contract is completely irreversible.
To find out how you would go about canceling a contract, read this article.