Hoe to update Blanket Sales Agreement in R12?

I would like to update Blanket sales agreement in R12. I am using oe_blanket_pub.process_blanket to update the BSA but it errors out.

Please let me know if there is any API which updates BSA in R12.

Below is the piece of code

h_rec_type.operation	:='UPDATE';
h_rec_type.payment_term_id	:=v_header_rec.payment_term_id;
h_rec_type.shipping_instructions	:=v_header_rec.shipping_instructions;
h_rec_type.packing_instructions	:=v_header_rec.packing_instructions;
h_rec_type.price_list_name	:=v_header_rec.price_list_name;
h_rec_type.price_list_description