one party to the original treaty and one party to the amended treaty, the states will only be bound by the terms they both agreed upon. Treaties can also be amended informally by the treaty executive council when the changes are only procedural, technical change in customary international law can also amend a treaty, where state behavior evinces a new interpretation of the legal obligations under the treaty. Minor corrections to a treaty may be adopted by a procès-verbal; but a procès-verbal is generally reserved for changes to rectify obvious errors in the text adopted, i.e., where the text adopted does not correctly reflect the intention of the parties adopting it. Protocols In international law and international relations, a protocol is generally a treaty or international agreement that supplements a previous treaty or international agreement. A protocol can amend the previous treaty or add additional provisions. Parties to the earlier agreement are not required to adopt the protocol, and this is sometimes made explicit, especially where many parties to the first agreement do not support the protocol. A notable example is the United Nations Framework Convention on Climate Change (UNFCCC), which established a general framework for the development of binding greenhouse gas emission limits, followed by the Kyoto Protocol contained the specific provisions and regulations later agreed upon. Execution and implementation Treaties may be seen as "self-executing", in that merely becoming a party puts the treaty and all of its obligations in action. Other treaties may be non-self-executing and require 'implementing legislation'—a change in the domestic law of a state party that will direct or enable it to fulfill treaty obligations. An example of a treaty requiring such legislation would be one mandating local prosecution by a party for particular crimes. The division between the two is often not clear and is often politicized in disagreements within a government over a treaty, since a non-self-executing treaty cannot be acted on without the proper change in domestic law. If a treaty requires implementing legislation, a state may be in default of its obligations by the failure of its legislature to pass the necessary domestic laws. Interpretation The language of treaties, like that of any law or contract, must be interpreted when the wording does not seem clear, or it is not immediately apparent how it should be applied in a perhaps unforeseen circumstance. The Vienna Convention states that treaties are to