Is it possible to send an xpdf process a signal that causes it to reload the file being displayed?

On page change, redraw, or Reload command, xpdf will reload the file it is currently displaying. Is it possible to cause xpdf to reload the file by sending a signal? Which signal? (I am basically looking for the functionality offered by xpdf -remote ServerName -reload, except I want to apply it to an xpdf that was not launched with the -remote option.)