From a General Contractor point of view, you will need to keep separate logs for the change orders that your subcontractor submitted to you and the change orders that you submit to the owner, which is kind of obvious. However make sure that those two logs are related to each other and refer to each other otherwise things will get very confusing. If you are on a large project with an established system and especially using software like prolog for instance things it is something else…. But if you ar eon a job trying to keep track of things with excel logs, you will need to make accurate references on everything, including work tickets, RFIs and other documents. More on what should be included on a change order log in another post