Q: How to change the user name on my macbook pro?

Simple solution:

Create a new user account with your username and password. Log into this new account. Before deleting the old account you should locate all Microsoft Office files and folders located in the original /Home/Library/ folder. You will also want to get the two com.microsoft...plist files in the /Library/Preferences/ folder.

Once the files and folders have transferred into your new account, delete the old one.

Click on the lock icon and enter the admin password when requested. Then click on the Add [+] button button just below Login Options. Carefully fill in the required information to create the account, and be sure the account has Administrator status. Click the OK button when you are finished.

There are two files located in /Library/Preferences/ folder:

com.microsoft.office.licensing.plist

com.microsoft.PlayReady.plist

You want to copy the /Library/Application Support/Microsoft/ folder

You want to copy the /Users/oldacct/Library/Application Support/Microsoft/ folder

Then there are a lot of files for Office in /Users/oldacct/Library/Preferences/:

com.microsoft.autoupdate2.plist

com.microsoft.EquationEditor.plist

com.microsoft.error_reporting.plist

com.microsoft.Excel.plist

com.microsoft.office.plist

com.microsoft.office.setupassistant.plist

com.microsoft.outlook.office_reminders.plist

com.microsoft.Powerpoint.plist

com.microsoft.visual_basic.plist

com.microsoft.visualbasic.plist

com.microsoft.Word.plist

Microsoft folder

SSo what if I don't know the password to the admin account? I just bought my MacBook but I can't add or delete accounts cause I don't know the previous owners username or password. Please help it's really frustrating