2702873 - Error 06800: While Modifying Item via App "Manage Purchase Requisitions"

System does not allow the modification of the purchase requisition item via "Manage Purchase Requisitions" or "Manage Purchase Requisitions - Professional" apps and throws error incase follow-on document like PO has been created even for any of the other requisition items.

•  SAP Fiori 
•  Sourcing & Procurement
•  SAP S/4HANA Cloud All versions 

06800, Manage Purchase Requisitions, Manage Purchase Requisitions - Professional, Manage purchase requisitions professional, manage purchase requisition, purchase requisition, manage, Modify, Edit, Follow-on, Requisition , KBA , MM-PUR-REQ , Purchase Requisitions , MM-FIO-PUR-REQ-PRF , Manage Purchase Requisitions – Professional , MM-FIO-PUR-REQ-SOC , Fiori UI for Sourcing Purchase Requisitions , How To