Maintaining the Assignment Between Event with Field Restrictions and Change Document 
To restrict the event creation with regard to whether the change refers to specific fields or fulfills specific conditions, proceed initially as described under Maintaining the Assignment Between Change Document and Event Without Field Restrictions.
Select a change document-event assignment and call the dependent view Complex Field Restrictions.
This displays the screen for changing a condition. You process the condition in the upper half of the screen. An existing condition may already be displayed there.
Determine the condition that is to trigger the event.
See the documentation on the condition editor.
Exit the condition editor and select Save.
Note
Via the dependent view Field Restrictions, you can determine a more simple field restriction (comparison of an "old" value with a "new" value). From there you can also go to the condition editor via expert mode.