Change requisition approval.

Hello,

Currently when an assistant does a requisition this goes to the financial manager for approval, then goes to the General Manager for approval, when is approved, the assistant creates the PO, and then goes again through the same flow.  

This means the purchase has to go for the general manager twice.

I would like to change the approval flow this way:

When the assistant does the requisition, this goes to the Financial Manager and he approves it.  When the assistant does the PO, want this to go directly to the General Manager.

I am new in PO, Can any one help me to achive this.