How to change the FROM clause of multiple views at once
I am not sure if I fully understood your question however if it is about changing source table of selected views or all views, you can do the same using SSMS(SQL Server Management Studio).

You can generate scripts from database as below:



In the screen, either you can select all view or select the one that you need as below:



You can save them to a new query window:



Alternatively you can save this as a SQL file. Now, using simple text editor, you can do replace all from existing table name to new table name and either you can run them directly in the new query window or can execute them from SQL file. This file can be handy whenever there is change in table name, you can just find and replace table and would work for you.

One great point made by Aaron Bertrand, if you create another view(only one) wherein you just include the definition as :

create view NotChangingName
as
Select * from changingName


You don't need to change each view, just one change will be sufficient.

Hope this helps.