How to logout Sign off from Skype on Nokia Lumia WP7.5 WP8 phones

Microsoft is the owner of Skype. And some of Skype users who is using Skype on Microsoft's Windows Phones are troubling to sign out from Skype account on a Windows phone Device. Such as i am using Skype on Nokia Lumia 920 Windows 8 Phone. And i did face a huge problem to get signed out from Skype on my Lumia Windows phone. And i have search each and every option get log off from my Skype account