What should I say to my stepmoms previous stepchild?

[Cat]

Well, I can sorta relate to the whole having another sibling and not having met thing. Maybe just keep it simple and say something like "Hello, I'm having a bit of a problem with -bla bla bla bla bla *insert actual text*-" and whatever. But if you can't, just think of a way easy for yourself to do it..

And I'm making no sense once again! Ugh.. Well, good luck. Hope you find the right words and get to talk to 'er.