\markboth{left head}{right head}
\markright{right head}
The \markboth and \markright commands are used in
conjunction with the page style myheadings for setting either
both or just the right heading. In addition to their use with the
myheadings page style, you can use them to override the normal
headings in the headings style, since LaTeX uses these same
commands to generate those heads. You should note that a "left-hand
heading" is generated by the last \markboth command before the
end of the page, while a "right-hand heading" is generated by the first
\markboth or \markright that comes on the page if there is
one, otherwise by the last one before the page.