need to reset to factory settings

Click on the link to read 'What to do before selling or giving away your Mac.' --> http://support.apple.com/HT201065

That article accomplishes what you said you wanted. It removes all traces of your information, and leaves the Mac ready to create a new User and establish a connection to iCloud for a new Apple-ID.

Anything less will be problematic for the new user and for you.

I just want to reset my laptop