I have an assembly, i edit a part in separate window, if I want to modify this part to see what it looks like in my assembly, then I would create a new configuration, I want to make it longer, but I want to be able to go back to the original length. I have read the help file on this and don't understand locked and unlocked. I am trying again to understand this. I want to try a "different part" without creating a new part. do I unlock everything to edit the part and show the new length in the assembly?