You use this function, if you are referencing a reference operation set (or reference rate routing) in a routing (or rate routing) and want to convert the referenced operations to normal operations.
You can edit unlocked operations exactly like normal operations in a routing (or rate routing). In particular you can:
change the data of unlocked operations
insert other operations between unlocked operations
Changes that you make in the reference operation set (or reference rate routing) after unlocking have no effect on the routing (or rate routing)