Macro to assign styles?

Is it possible to write a macro in Word 2000 to assign
styles in a document? For example, if a client gives me an
unformatted document and I want to assign "Header 1" to
every line that's 14pt/all caps/bold italic/12 points
after/keep with next, "Header 2" to every line that's
12pt/u&lc/bold/6 points after, etc., is that possible? Any
tips to automate formatting super-long documents are
helpful. I spend an inordinate amount of time clicking the
cursor on a line and assigning a style...even with a
keyboard shortcut, it takes a long time.