Hi Vipul,
I don't believe RA supports interacting with desktop popups. So I don't think you will be able to do what you're looking to do. However, you may improve your chances of getting this to work by configuring your Nolio Agent service -> Log On tab and put a check in the checkbox for "Allow service to interact with desktop".
If this still doesn't do the trick then:
a. maybe others here can offer some advice; or
b. maybe you could provide some more information as to who, what, why, when, and how this interaction is needed so that we might be able to come up with an alternative approach.
Kind regards,
Gregg