How do you save a document with a new name?

OK I decided to go with Pages as my document editor on my iPad 2. It seems to be powerful enough to do the kind of text editing that I need to do. I need some tables, a few graphics, headers, footers, etc. You know the basic stuff. I am not going to try to write a dissertation or thesis on my iPad, but I need to be able to write memos and some work documents.

I am having a hard time learning the Apple way of doing things I guess. Must be too many years on a PC using Microsoft Office.

But I need to know how to open an existing document, make some changes and then save it with a new name so I don't overwrite my original document? Just a basic "Save As" function.

Is this possible? Or has Apple devised a way that I am just not seeing yet?