Unable to submit draft PO for approval using REST API

Summary: While submitting Draft PO for approval using REST API service, we are getting error "Invalid operation create for the specified resource." Kindly assist on resolving this error

Content (required):

(1) While submitting Draft PO for approval using REST API service, we are getting error "Invalid operation create for the specified resource." Kindly assist on resolving this error.

Resource or Reference: https://docs.oracle.com/en/cloud/saas/procurement/22a/fapra/op-draftpurchaseorders-draftpurchaseordersuniqid-x-operations-0.html

(2) Let us know how we can submit a Change Order PO for approval using REST API Service, do we need to use Resubmit a purchase order for approval service?