'Leave an e-mail' plugin

Hi,

I’m running a website with software and I want to install ‘leave an e-mail’ feature.

Sorry for noob description, but I don’t have the name for it, but it works like this:
– customer visit my website
– customer wants to leave a website and he press ‘X’ in the corner
– there is an additional page and information ‘leave a number or e-mail’, that we can contact you and give a special offer etc.

Is there somekind of plugin dedicated for WP which works similar to this?

Thanks
V.