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. 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.  Prior to 1871, the U.S. government regularly entered into contracts with Indians, but the Indian Appropriations Act of March 3, 1871 (Chapter 120, 16 Stat. 563) had annexed a horseman (25.C No. 71) who effectively terminated the presidential treaty by presenting that no Indian nation or tribe can be recognized as a nation, tribe or independent power – with which the United States can enter into contractual contracts. After 1871, the federal government continued to maintain similar contractual relations with Indian tribes through agreements, statutes and executive ordinances.  The separation between the two is often unclear and is often politicized in disagreements within a government over a treaty, as a contract cannot be implemented without the correct modification of national legislation. When a treaty requires laws of application, a state may be late in its obligations if its legislator does not pass the necessary national laws. In India, the themes are divided into three lists: the Union, the State and the Simultaneous. In the normal legislative process, issues on the trade union list must be regulated by law by the Indian parliament. For the subjects on the national list, only the state legislator can legislate. Both governments can legislate on subjects on the same list.
However, for the implementation of international treaties, Parliament can legislate on any subject and even repeal the general distribution of lists of subjects. A treaty is a formal and binding written agreement that is concluded by actors in international law, usually sovereign states and international organizations, but may involve individuals and other actors.  A treaty can also be described as an international agreement, protocol, treaty, convention, pact or exchange of letters. Regardless of terminology, only instruments that are binding on the parties are considered treaties of international law.  A treaty is binding under international law. A party`s consent to a contract is void if it has been issued by an agent or entity without the power to do so in accordance with the national laws of that state. States are reluctant to investigate the internal affairs and processes of other states and, therefore, a “clear violation” is necessary, so it “would be objectively obvious to any state dealing with the issue.”