Rename a Database Diagram (Visual Database Tools)
You can rename a database diagram in Object Explorer. Requires ALTER permission on the database.
To rename a database diagram
In Object Explorer, expand the Database Diagrams folder.
Right-click the database diagram that you want to rename.
Choose Rename on the shortcut menu.
An edit box is opened around the diagram name in the Object Explorer.
Enter the new name for the database diagram and press Enter.
The database diagram appears in Object Explorer with the new name.