Edit additional details on the order?

Hi, hope someone out there can help!

I’ve set up a pull-down menu on checkout to have people choose from an option, but I also need the ability to change what they chose on their order once it’s been placed, though. Currently, it’s set up under the “Additional” tab as “Select Options”, but if I receive an order where someone chose an option, I can’t go back in later to change it if need be. Is there a way to do this, even if it’s manual and just requires typing in the change instead of selecting from the same list?

Thanks!