Task Status tied to Change Approval

HP SM 9.4

Brand new to the forums and HP SM not sure yet where this question fits.

I've had an Environment field (Dev, Test, Prod) added to our Task Module and would like to make sure Prod Tasks do not move to the assigned status unless an assignee has been picked and the parent RFC has been approved by CAB. I'm assuming this is a minor condition added to the line where the status is changed for the task.  However, not being a programmer any suggestions on how to do this?