Assignment Manager - Required Fields

Hello,

We are in a new Assignment Manager implementation and wanted to check how to configure the below

Object -> Service Request

Wanted to add an Assignment Rule to check if there is a contact on the SR. Say, if there is a contact, would like to assign to a person in Employee Candidate.

Can you please help on how to write a Rule to check required property. Please note : We do not want this to be matched to any criteria value. (Include/Include All looks for a criteria value match)

So there are 4 rules preceeding this rule in that rule group , that checks for other matches - values. When those 4 fail, the said rule should look up if there is a Contact on SR. and assign to an Employee candidate