Marking the order as unfulfilled so I can change the address

I have an incorrect address on my orders. The print-on-demand service I am using is asking me to make changes to the address before submitting. I need to add a phone number and remove the # from the apartment number. Shopify says that I can change the address of the order if I mark it as unfulfilled and I am unable to do that. I need this resolved so I can process my order through my shop.

I think it would help if you explain why can’t unfulfill the line items, and include what you’ve tried.

For example, have you unarchived the order, clicked the 3 dots in the fulfillment order to see your options (or contacted the store admin, if you don’t have access), etc.