Data Management Capabilities > Managing Part Structures > Windchill Options and Variants Capabilities > Working with Option Sets > Merging Option Sets > Removing Merged Choices and Rules
  
Removing Merged Choices and Rules
If you wish to add or remove the choices or rules from a merged option set, PTC recommends that you unmerge the option set before making modifications. You can merge the option sets after the modifications are made.
To unmerge, on the part information page of the top-level product, click Actions > Remove Merged Items.
The action removes the merged choices and local rules that were added from a lower-level option set. However, it does not remove the local rules that were created in the top-level option set after the merge. If any top-level local rules refer to the lower-level choices that are removed, those local rules remain invalid until the choices are merged back.