Multiple Personalities: Is it Normal?

while no, people with BPD don't have alternate "personalities" (since that would be DID or OSDD-1), a lot of pwBPD report having different "modes". read a bit about secondary dissociation from the theory of structural dissociation of the personality, it describes it

Do you mean like if you're with a different freind group and you're personality changes?

Hmmm...maybe your thinking of disassociate disorder.

Borderline personality disorder does not mean your personalities change