If no writing exists, revoking a gratuitous assignment that has not been performed is extremely easy (because no physical transfer has taken place).
It can be revoked by an assignor later assigning the same right (the last assignment controls), the death or incapacity of the assignor, or by the delivery of notification of revocation to the assignee or obligor.
Methods of Assignment or Delegation – The rights under a contract can be assigned or the duties delegated through agreement between the assignor and assignee.
Assignments/delegations can be a gift or an exchange for other value.
If a court adjudicates the matter, the assignee winning at court may be vested with the authority to establish priority in performance of assigned rights.
Novations – If the assignee executes a novation, the novation establishes priority.Cleo later verbally assigns her rights to receive payment to Steve.Austin complains to Cleo about her subsequent assignment.A novation is a new contract between individuals that replaces a party to the contract or obligations or rights under the agreement.Written Assignment – If a later assignee receives a written assignment capable of transfer that is not in writing, she will have rights superior to those of an earlier assignee.Particularly, an assignment that greatly increases a party’s delivery requirements cannot be assigned.Doing so may detriment the obligor who has to meet a new (and possibly more taxing) delivery schedule.Modification after Assignment – Generally, a contract cannot be modified after assignment.As previously discussed, once a contract has vested, the parties generally cannot modify the contract in a way that impairs the assignee’s rights.Increases Burden or Risk – Generally, any contract that materially increases the other party’s burden, risk, or ability to receive return performance is not delegable.As such, requirement contracts generally cannot be delegated because the producer’s duty depends on the individual output requirements of the purchaser.