This document details how to delete/reset network adapters in OS X.
Note: You will need Administrative privileges on the computer to perform this action.
Open System Preferences from within the Apple menu.
Choose the Network option.
Highlight the network adapter that is causing difficulties and press the "-" sign in the bottom of the left hand column.
Click Apply in the bottom right hand corner of the page to apply these changes.
It is strongly recommended that you restart the computer to apply these changes.
After restarting the machine, open the Network panel by repeating Steps 1-2.
If the adapters which you previously removed have not appeared, you will need to press the "+" sign in the bottom of the left hand column.
Choose the interface of the adapter that you deleted prior to restarting your computer and click Create.
After clicking Apply, this adapter should be added and functional once again.