Microsoft Graph API calling in ABAP to read Sharepoint documents

Hi SAP Gurus, I am trying to Call Microsoft Graph API in SAP ABAP to read the Sharepoint documents. For one the field from Share point there was NO Index Created and I was Instructed to pass the Header Parameters as 'Prefer: HonorNonIndexedQueriesWarningMayFailRandomly'; even though I pass these parameters in the my SAP Code - Header parameter, my Code is NOT accepting. If any one can help to share the sample Code that would be more helpful. Thanks,Sri.