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.
Note:
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.
Tip:
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.