Related Clues:

• It may consist of regrets
• Letters sometimes preceding a phone no.
• Evite.com request
• "Reply, pls."
• ''Let us know,'' on an invitation (Abbr.)
• ''Let us know,'' initially
• Confirm, in a way
• Regrets, perhaps
• "Let us know," to an invitee
• Answer, shortly
• SASE contents, perhaps
• Invitation acronym
• Party thrower's request
• Say you will, or won't, be there
• Invitation ltrs.