by having a agreement
Congress
The Congress has to agree with treaties. If they don't it cannot be made.
We have a bicameral congress consisting of a house of Representatives and senate. A majority in both house must approve a proposal to amend the constitution.
Its so the country is properly represented as a whole on something as big as adding an amendment to the constitution.
Interestingly, the constitution doesn't say a lot about how to become a state. It does say "New States may be admitted by the Congress into this Union," and it also says that a new state may not be created out of the territory of an existing state, nor can two or more states be merged into one, unless both the Congress and all the state legislatures involved agree to it. A state must have its own constitution, but it must also agree to accept the authority of the US Constitution. Today, if a new territory wants to join the United States, it must express its desire for statehood to Congress, and it is up to Congress whether to approve it or not.
All laws must agree with the United States Constitution. If a law does not abide by the constitution, it can be challenged by the Supreme court.
The US Constitution does not provide for referendums on national issues. I think if you want Congress to do something different, you must work to elect representatives and Senators who agree .But keep in mind many people will not agree with you; you can't force Congress to do just what YOU (or even you and 10,000 others) want.
They must follow the rules of the constitution .
Amendments to the constitution must be ratified by the states. To become part of the Constitution the Amendment must be approved by three-fourths of the states.
two thirds
Constitutional amendments must first pass both houses of congress, and they are then sent to the states to be ratified. To become a law, 3/4 of the states must agree to ratify an amendment. This is to make sure that amending the constitution is difficult and requires a lot of thought before it happens. So, to sum up, after a proposed amendment is approved by congress, it must then go to the individual states; if enough states vote to approve it, the amendment becomes a part of the constitution.
Congress. The constitution states Congress must approve it.