Oracle Applications :Purchasing :Approval Hierarchy
Can We Change Purchasing Approval Hierarchy Form Employee Supervisor Hierarchy To Position Hierarchy?
Purchasing -> Setup -> personnel -> Position Hierarchy
Then take this position hierarchy and attach it to the appropriate document types:
Purchasing -> Setup -> Purchasing -> Document Types
Purchase Order Standard -> Update:
Approval Workflow = PO Approval
Workflow Start Process = PO Approval Top Process
Forward Method = Hierarchy
Default Hierarch = <your hierarchy defined above>