Sketcher > Modifying a Section > To Resolve a Conflict
  
To Resolve a Conflict
When you add a dimension or constraint that conflicts or is redundant with existing strong dimensions or constraints, Sketcher highlights dimensions and constraints in conflict and asks you to remove one of the highlighted constraints or dimensions. Use the following options from the Resolve Sketch dialog box when you resolve the conflict:
Undo—Undo changes to bring the section to the state it was in just before the action that lead to the conflict. The Redo command is not available after you choose Undo, because the last operation was not finished.
Delete—Select a constraint or dimension to remove.
Dim > Ref—Select a dimension to convert to a reference.
 
* The Dim > Ref command is only available if there are dimensions in conflict.
Explain—Select a constraint to get a description of the constraint. Sketcher highlights entities associated with this constraint.