Hi nickip212.
The answer is yes!

I've had numerous alters that have changed their form, identities and names every now and then. I'm not sure why this happens and I haven't asked. My alters only say that the older alter who's place they took, isn't anymore here.
I guess that new alters can directly replace old alters when they have to leave the system.

Just couple days ago I lost two of my oldest alters and new ones took their places. They say that the old ones are now part of me and that they've never actually left.
Integrationg maybe?
*shrugs*I've also noticed that alters can contract new alters from themselves and it confuses me to think that the old alter's personality has changed. But it's actually a twin sister/brother of the older alter. Maybe this is what happened to Amy?
Another thing that I've noticed is that alters change into their true self when I understand them properly. It's like they're big living puzzles that shed layers.
I hope this helped.