Ratification is a principal's legal confirmation of an act of its agent. In international law, ratification is the process by which a state declares its consent to be bound to a treaty. In the case of bilateral treaties, ratification is usually accomplished by exchanging the requisite instruments, and in the case of multilateral treaties, the usual procedure is for the depositary to collect the ratifications of all states, keeping all parties informed of the situation. The institution of ratification grants states the necessary time-frame to seek the required approval for the treaty on the domestic level and to enact the necessary legislation to give domestic effect to that treaty. The term applies to private contract law, international treaties, and constitutions in federal states such as the United States and Canada. The term is also used in parliamentary procedure in deliberative assemblies. In contract law, the need for ratification often arises in two ways: if the agent attempts to bind the principal despite lacking the authority to do so; and if the principal authorizes the agent to make an agreement, but reserves the right to approve it. An example of the former situation is an employee not normally responsible for procuring supplies contracting to do so on the employer's behalf. The employer's choice on discovering the contract is to ratify it or to repudiate it. The latter situation is common in trade union collective bargaining agreements. The union authorizes one or more people to negotiate and sign an agreement with management. A collective bargaining agreement can not become legally binding until the union members ratify the agreement. If the union members do not approve it, the agreement is void, and negotiations resume. A deliberative assembly, using parliamentary procedure, could ratify action that otherwise was not validly taken. For example, action taken where there was no quorum at the meeting is not valid until it is later ratified at a meeting where a quorum is present.