Related Clues:

• 'Eureka!' cause
• Invitation request
• Response
• Undo a secession
• Letters on an invitation
• Request of an invitee, briefly
• Puzzle solver's goal
• Jerk one's knee, perhaps
• Invite letters
• Say ''ouch!'' when pinched, e.g.
• Prove wrong
• Punch back instinctively
• Acknowledgement
• ''Please reply''
• Do a double-take