Whilst it is not impossible it is not something that is easy either. You would have to have a good knowledge of both sql queries and phpBB database structure - and plenty of time!
It may be preferable to just leave the "old" board as an archive and not allow any postings to be made to it.
Remember: You only know what you know and - you don't know what you don't know!
My CDB Contributions | How to install an extension
I will not be accepting translations for any of my extensions in Github - please post any translations in the appropriate topic.
No support requests via PM or email as they will be ignored