Update Customer on Project with AR Activity

Hi

We have a number of Customers set up incorrectly on a Project that has AR activity . Users have to reverse the AR activity and then create a new project and assign the correct Customer to reprocess the transactions. Has anyone come across any other automated or simplified workaround with this kind of scenario?

We use Customer Merge when we only have 1 Site at a Customer level but this does not work when a Customer has multiple sites.

thank you