How do you get the effective date based on the action reason value?

Summary:

I want to get the parental leave start date which is the effective start date based on the action reason = 'On parental leave'

Content (required):

I have the code below but it does not seem to work.

Thanks in advanced.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):

CASE 

WHEN LOCATE('On parental leave', "Workforce Management - Worker Assignment Real Time"."Worker Assignment Details"."Action Reason") > 0 THEN THEN "Worker"."Assignment Start Date"  END