can a local join a national
 

i would never drop my sorority, but i had a sister who dropped and wanted to join a national, i was wondering if she can actually do that bc i have heard lots of different answers about it. can anyone help me out?

If it's an NPC group that she wants to join, there's nothing on the NPC side that would stop her. Some individual members might have opinions against her because she dropped (and she might have to explain) but there's nothing against it.

Your chapter might have rules against being in both but she's no longer a member of your group so those rules couldn't really be enforced anyway.

Short answer: Yes, she can join a national.

There is an NPC rule that prohibits anyone who's been initiated into one NPC sorority from ever joining another, even if she deaffiliates from the first. I'm not sure what the rules might be for non-NPC national sororities. But the NPC rule doesn't extend to locals - you can pledge and even be initiated into a local, deaffiliate, and then join an NPC sorority.

However, if the local is a member of the college's Panhel, Panhel may have adopted a rule that you can't initiate into the local, deaffiliate, and join a national (in the spirit of the NPC rule).