How do I take my iCloud account off my iPhone?

I need help regarding my iPhone 5, where I forgot my iCloud ID and password, since I forgot the screen pattern and was advised to update the firmware, my data files were all lost where I forgot when I entered iCloud... I looked for a method in the manual in the iPhone box. there isn't... is there a way to open my icloud or delete icloud from my iphone

[Re-Titled by Moderator]