There are three ways to change an existing treaty. First, a formal change requires that States Parties be forced to go through the ratification process again. The renegotiation of the treaty provisions can be long and time-consuming and often some parties to the original treaty will not become parties to the amended treaty. In determining the legal obligations of states, a party to the original treaty and a party to the amended treaty, states are bound only by the conditions on which they have agreed. Contracts may also be amended informally by the treaty office if the amendments are procedural in nature, and technical changes in customary international law may also alter a contract in which the state`s conduct presents a reinterpreting interpretation of legal obligations arising from the treaty. Minor corrections to a contract may be accepted by a minutes; However, a minutes are generally reserved for amendments to correct obvious errors in the adopted text, i.e. where the adopted text does not adequately reflect the parties` intention to adopt it. International contract law has been largely codified by the Vienna Convention on Treaty Law, which sets out the rules and procedures governing the establishment, modification and interpretation of contracts, as well as the resolution and resolution of disputes and alleged infringements.  Treaties are considered to be one of the oldest manifestations of international relations as the main source of international law.  Initially, international law did not accept and rejected contract reservations unless all parties accepted the same reservations.
However, in order to encourage as many states as possible to join the treaties, a more straightforward reserve rule has been established. While some treaties still explicitly prohibit any reservations, they are now generally accepted to the extent that they are not incompatible with the objectives and objectives of the treaty. According to the preamble to contract law, treaties are a source of international law. If an act or absence is condemned by international law, the law will not accept its international legality, even if it is authorized by domestic law.  This means that in the event of a conflict with domestic law, international law will always prevail.  In addition to treaties, there are other, less formal international agreements.