How to unlink Apple account from laptop? I'm going to have to trade in my work laptop and it's connected right now to my personal Apple account for things like the app store etc. How do I unlink the Apple account before I get a new computer?
What to do before selling or giving away your Mac

Learn how to back up and remove the data from your Mac before selling or giving the computer away.  

When preparing to sell or give away your Mac, you may want to erase some or all files from its hard drive. But first determine whether you should back up your computer and disable certain features and services. These steps show the recommended sequence of actions:


Deauthorize your computer from iTunes, if applicable.
Back up your data using Time Machine or other backup methods for OS X Yosemite, Mavericks or Mountain Lion.
If you use Find My Mac or other iCloud features on this Mac, complete these steps:


Back up your iCloud content.
Choose Apple Menu () > System Preferences, then click iCloud.
Deselect the Find My Mac checkbox.
Sign out of iCloud. When you sign out of iCloud, you're asked whether you want to remove iCloud data from your Mac. Removing iCloud data in this way makes sure that the data isn't also removed from any of your other devices that are using the same iCloud account.

If you're using OS X Mountain Lion v10.8 or later, sign out of iMessage:


In the Messages app, choose Preferences > Accounts.
Select your iMessage account, then click Sign Out.

Reformat your hard drive and reinstall OS X. Follow the appropriate instructions:


OS X Yosemite
OS X Mavericks
OS X Mountain Lion
OS X Lion

After you reformat your hard drive and reinstall OS X, the computer restarts to a Welcome screen and asks you to choose a country or region. If you want to leave the Mac in an out-of-box state, don't continue with the setup of your system. Instead, press Command-Q to shut down the Mac. When the new owner turns on the Mac, the Setup Assistant will guide them through the setup process.