Charles, it is a document that has already been created with multiple letters to multiple people. There is no mail merge to do or redo at this point. Also, I don't have headers or footers in this document, so I am not sure why that was thrown out there.

I wasn't sure I needed to state this, but apparently it is clear that I do. I am not interested in alternatives that would involve redoing the document. I am also not interested in any answers based on assumptions people have formed that go beyond what I initially stated. Once again, I would like to know how to make this happen:

All odd pages-1.6" top margin.
All even pages-1.0" top margin.
Done in one single series of steps, not manually setting different things page by page.