Are you talking about the pop up that shows up when clicked on "i" icon after the reference field in servicenow 

or in service portal pop up window 

Thanks,

Siva

HI,

Do you want to show RP once you click on any button.

If yes then you might have to do this using UI pages and Iframes.

Thanks,
Ashutosh Munot

No I was thinking of same type of popup you can have when you call on Ui Action button and call the GlideDialogForm for instance

Glide Dialog window is especially used for calling UI pages in servicenow 

Thanks

Siva