Update business unit of merged deactivated accounts

Hi,

I had a requirement wherein i need to merge one business unit into another. I was able to do it sucessfully. The only issue i faced is that, there are some accounts which were merged into another accounts and then deactivated. These accounts still remain the the old business unit. Is there a way to change the business unit of these merged deactivated accounts ? I tried with Excel import bulk update, but it shows error that the record does not exist. One solution i thought is updating these records using a console app. Can this be done using OOB features ?

Thanks,

Najm