You can rearrange the order of the Phone app tabs and/or delete the Favorites and Groups tabs.
From the Home screen, tap the Phone icon (in the QuickTap bar).
Tap the Menu icon (at the upper-right corner of the screen), then tap Edit tabs.
Drag a tab handle to move it to the position where you want it in the list.
Tap the Favorites or Groups checkbox (checkmark displays the tab, no checkmark deletes it from the Phone app tabs bar).
When you're finished making changes, tap Save (at the bottom of the screen).