How to prevent sending mail to Initiator

I'm trying to prevent workflow to send mail to initiator when PO is approved.

I copied the workflow from default PO approval workflow. There is a step named (PO is approved) and the task of that step is TS20000168.

Below that windowd there is Agents windows. I'm cleaning the agent input. But still I get the mail which says (PO XXX is approved), when the PO is approved.

Any one help me about getting rid of this notification.

Here is the workflow (it's Turkish, by the way );

1- Workflow

2- Step