Possible Clues:

• 'Right back ___!'
• ''Right back __!''
• "Right back ___!" ("Likewise!")
• "Back __!"
• 'Comin' ___!'
• "Right back —!"
• 'Back --!' ('Likewise!')
• See 6-Across
• 'Right back ___!' ('Likewise!')
• ''Right back ___!''