Form Acknowledgment Page problem

<form action='PageX.html' method='post'>
<input type='hidden' name='action' value='changepassword' />
<input type='hidden' name='n' value='PageX.html' />
<input name='submit' type='submit' value='Save' />

The information needs to be passed to PageX, but I'd like for the user to land on "PageY" instead. How could I do that?

Thanks