Ship To Change prevention in order entry level

Hi

During Sales order entry,  When user keys in order header with Ship To / Sold To , we know all associated values gets defaulted into Header / details areas, But before saving the order when user modifies Ship To Sold to.  The defaulted values like Pay instrument, Freight handling code etc. from previous Ship To/ Sold To would be carrying all through the order process.  I understand this is process violation, How to prevent during modification stage  of Ship To / Sold To ?. i am looking for an approach if this can throw hard error, Then user bound  to