Could not able to update sales order line data using order interface tables order_import

Dear Team ,

As part of sales order bulk update , I am using oe_headers_iface_all, oe_lines_iface_all to update the records. But it not working using order import program.

getting following error :

You are trying to insert an existing order or update an order that does not exist. Please enter a correct operation code.

where as same data is processing using oe_order_pub API.

Could you please help me  out to resolve this issue.

Please provide sample script if you have handy that will be  great.

Regards

Madhusudhan P

Mob : +91 99593 111162