I don't think that's possible anymore. Broom says this piano doesn't do time travel; it does dimensional gates. So this Etain [i]is[/i] from another universe...just one that's about 18 years ahead of ours. She can't go back. Even if she could, I wouldn't recommend it. While there are theories stating that it wouldn't erase this version of her from existence, mucking about with time is pretty much always a bad idea.