You can use the Peer Variables command to edit variables for parts within an assembly or subassembly.
In an assembly, Choose Tools tab→Variables group→Peer Variables
Select the part or subassembly that contains the variable you want to edit.
In the Variable Table, select the variable you want to edit.
You can change any of a variable's attributes except its type and unit type.
On the Variable Table, in the Name column, type a new name.
On the Variable Table, in the Value column, type a new value.
In the Formula column, click the cell and use one of several methods to create a new formula.
You can use the Peer Variables command to edit a part variable when you are in the assembly document or when you have in-place activated a part within an assembly.