Amendment
The "Great Law of Peace" known generally as the Iroquois Constitution was an oral law from 1090 AD through sometime between 1100 AD and 1700 AD; it is unknown when it was first written. It was translated to English in the early 1700's.
A change to a constitution is called an "amendment."A ballot vote on a prospective law is called a referendum.
The Constitutional convention was called to create and write the law of the land (Constitution).
The German constitution is called the Grundgesetz. It translates in English to "Basic Law".
Constitution
The Constitution is the highest law in the United States.
The law of a politically organized body is called a constitution.
The US Constitution is called The Supreme Law of the Land.
Ratification
Yes. We have had a constitution for almost 200 years. It is called the U.S. Constitution, A.K.A "The Law of The Land."
9 out of 13 states had to approve or ratify. The process was called ratification
None ! The UK does not have a written constitution ! I suppose what we have in its place is called 'Common Law', but no, Constitution we do not have.