Add line through requester-initiated change order with API

Summary:

I want to add a new line in the existing purchas eorder through requester-initiated Change Order process. I am able to do it post adding the privilege 'Create Purchase Order Line as Procurement Requester' in the instance. However, when I am trying to do the same through rest api, it is giving me an error that

<NUMBER>PO-2055145</NUMBER><TEXT>You must provide a valid value for the ChangeOrderInitiatingParty attribute. The current value is REQUESTER.</TEXT>

Payload:

<types:changeOrderEntry>
<tns:POHeaderId>XXXXXXXXXXXXXXXX</tns:POHeaderId>
<tns:SoldToLegalEntityId>XXXXXXXXXXXXXXX</tns:SoldToLegalEntityId>
<tns:ApprovalActionCode>NONE</tns:ApprovalActionCode>
<tns:ChangeOrderDescription>TEST</tns:ChangeOrderDescription>