How To Use REST API For PROMOTION Action

Summary

We are using a REST API call to trigger a PROMOTION Action in Fusion HCM but we are getting an error of invalid json string

Content

API HEADER: 
Effective-Of:RangeMode=UPDATE;RangeStartDate=2019-05-13;Authorization= 

API PAYLOAD: 
{"LocationId":"300000042487375","JobId":"300000002372214","ActionCode":"PROMOTION","ActionReasonCode":"PRCO"} 

ERROR MESSAGE RETURNED: 
Error: Fail to update Assignment using WebAPI.;RestAPIError: StatusCode: BadRequest; ResponseStatus: Completed; Server: Oracle-HTTP-Server;UpdateAssignment; Exception: Invalid JSON stringContent:The action PROMOTION is not supported. (PER-1531830);; 

 

Is there something wrong with the Payload or Header format that we are using?

Version

r13