Create Workflow rule when date field no longer blank
I am trying to create Workflow rule that will trigger with a date field is no longer blank. In the Rule Criteria section one sample I've tried is:
Field: Date Due
Operator: not equal to
I've tried the other operators like Contains, Does not Contain, Includes, and Excludes.. but can't seem to find a combination that works with anything I put in the Value area like BLANK or NULL.
Do I need to write this as a forumla instead of usiting "criteria are met"?