The formal amendment process requires these two
governments to work together to ratify
constitutional amendments.

The state governments and the federal government are required to work together to ratify the constitutional amendments.

Explanation:

An amendment to the constitution can either be proposed by the United States Congress or by at least 38 of the 50 state governments. No matter who proposes the amendment, it has to be ratified by at least 2/3rd of the existent state governments and also the United States Congress for it to become a part of the Constitution.