Best-practice way to lower all ceiling heights both floor 1 and 0 (basement)

[GeneDavis]

I want to leave the roof right where it is, but I have a plan with 10' plate heights common everwhere, main floor and basement.

 

This one is in an HOA neigborhood with a height limit.  I want to keep absolute highest ridge where it is, and basement floor elevation absolute also.  I will edit the roof after.

 

 

How to do and sequence, please.

Edited March 26, 2020 by GeneDavis

[Renerabbitt]

Edit/Default Settings/Floors and Rooms/Floor Levels/

[GeneDavis]

Nope. Worked for floor 0, but not for floor 1.  My default for floor 1 is 9' and I made it all 10' before placing interior walls.

 

So floor 1 the default is where I want to go, but all the rooms are non-default and specified at 10'.