The first time you attempt to rename a Level or associated, non duplicated, Floor Plan or Ceiling Plan, REVIT will prompt you to rename the corresponding Level and Views. . . . . depending on which one you are renaming.
You can reply Yes or No to the 'Would you like to rename. . . . " question.
Here is the message when renaming a Level for the first time.
Here is the Message when you rename a Floor Plan or Ceiling Plan.
Take note of the slight variation.
As long as you answer 'Yes' to either message above REVIT will rename the views and the level and keep them synchronized with the same name.
The problem starts when you click the 'No' button and then later decide you would rather have them named the same.
There is no problem if you want to keep the Level name and change the Floor Plan or Ceiling Plan names.
But if you want to change the Level name to match the plan views you get an error:
"The name entered is already in use. Enter a unique name."
It is possible to rename the Level so it matches plan view if you follow these steps in this order.
Pick the name you want the Views and Level to use. eg: Level 1
Rename both the Floor Plan and Ceiling Plan something different (not Level 1) and nothing already in use. This is a temporary name. eg: Level1x
Rename the Level to be Level 1
Rename the Floor Plan and Ceiling Plan to be Level 1.
They are all now synchronised. If you try renaming either the Floor Plan, Ceiling Plan or Level and you will get the 'renaming' message again.