reason codes for PO changes

Dear SAP professionals,

could you, please, help me. I want to create the reason codes that should be used by buyers while making the changes to the orders(quantities, delivery dates and etc) is it possible? As we face a lot of delays and want to track them according to what was the reason for delay(wrong engineering specification, supplier fault and etc. ) Can you give some tips, does it require any big changes? Can we do it at plant level?

Thank you in advance!

best regards