
3 respostas
Change your workflow rule to evaluate when a record is "created, and every time it’s edited." Then change your criteria formula to include ISBLANK(Date_Field__c), eg:
ISPICKVAL(Picklist_Field__c,"Complete") && ISBLANK(Date_Field__c)

ISPICKVAL(Picklist_Field__c,"Complete") && ISBLANK(Date_Field__c)