Account Payable invoice can be routed for approval using the AME Approval Management Engine. This whitepaper describes how to setup AME for use with invoice approvals, and shows how a invoice approval list is built based on the AME setup. Approvers in the AME based approver list are assigned to the requisition based on the AME rules setup for Account Payable invoice Approval transaction. The screenshots provided are based on 11i.AME.B, and some of the navigation details are specific to 11i.AME.B. However, most of the details provided are applicable to 11i.AME.A and higher including R12.
How to setup and use ame for purchase requisition approvals 2011-04-27
How to setup and use ame for purchase requisition approvals