Possible Clues:

• Hail ___
• Hail __
• Hail ___ (wave from the sidewalk)
• Words after call or hail
• Hail ___ (cry 'Taxi!')
• Hail — (yell "Taxi!")
• Call __
• Something to hail or call
• 'Call me ___' (old joke setup)
• "Okay, you're ___" (taxi joke punch line)