Cancel in Custom Preview

Jos?© Mario Neri

Excuse my bad English...

Using custom Preview with the code below:
FrxReport1.Preview := Frm_Preview.Preview;
if frxReport1.PrepareReport then
begin
frxReport1.ShowPreparedReport;
frm_Preview.ShowModal;
end;

Where in the preview form, in the button to Print associated the code:
Preview.Print;
How to know dialogue of impression the button it was pressed to cancel?
Thank's.

Jos?© Mario