If you have a number being used as a secondary number and need to revert it back to a regular number, here is how you do that:
1. Click your name in the top right corner and go to your "Numbers" screen.
2. Next to the number that is currently the secondary number, you will see this icon and this note to "see" the number it is set to be connected to:
3. Go to the number it says to "see" and click the secondary number icon:
4. Click the drop down menu, and unselect the number. Then click "apply"
5. Next you will see it now says "none selected". Click "Save".
6. The number is now no longer listed as a secondary number and the icon will be changed to a star.