Subscreen change/display problem

Hi,

I have a problem in dialogue program.I created a subscreen in preq(ME51N), when i go in ME53N, it's coming in display format.but when i go to menu bar->purchase requisition->display/change, and vice versa in ME52N to display format.it's not coming in change format.What i have to do for this one.

Thanks in advance,

Avinash