How can we use API (oe_order_pub.process_order) to update Cancel reason and comments for Sales Order

Hello,

I am using API (oe_order_pub.process_order) to cancel the Sales Order at Header level but even after i use following variables i am not able to see the Cancel reason from Front end.

1) l_header_rec.cancelled_flag := 'Y';

2) l_header_rec.change_reason := 'Not provided';

3) l_header_rec.change_reason := 'Sales order cancelled on';

Only the value gets update in OE_REASONS table and not shown from Front-End.

Navigation from Front-end: (Go to Sales Order Form--> Action button--> Cancel)

Please suggest which field i need to update so as that the values can be shown from front-end.