Resizing the dialog via JS

I can set the height of the dialog when it's initialized ( via the
options array).
However, how do I change the height of the dialog after it has been
created ( for example, after an ajax request?)
I've tried $(this).data("height.dialog", new_height); but it doesn't
resize the ui-dialog-content div, leaving the content inside the
dialog small.
Any help would be appreciated.
Bojan