[TSteven]

And just to be clear, the “new” local would not be able to use the NPC letters, ritual or any trademarks belonging to the NPC organization.

And any of the "new members" - those who had only been in the local sorority - would be able to affiliate with a national organization at any time. It might be frowned upon on your campus, but if one is not a member of a national organization, then they should be able to join one - if they meet that organization’s membership criteria etc.