Changed one letter

This is a list of winners from a New York Magazine contest in which
 contestants were to take a well-known expression in a foreign language,
 change a single letter, and provide a definition for a new expression.

 HARLEZ-VOUS FRANCAIS? -- Can you drive a French motorcycle?

 EX POST FUCTO -- Lost in the mail

 VENI, VIPI, VICI -- I came, I'm a very important person, I conquered.

 COGITO EGGO SUM -- I think; therefore I am a waffle.

 RIGOR MORRIS -- The cat is dead.

 REPONDEZ S'IL VOUS PLAID -- Honk if you're Scottish.

 QUE SERA SERF -- Life is feudal.

 LE ROI EST MORT.  JIVE LE ROI -- The king is dead. No kidding.

 POSH MORTEM -- Death styles of the rich and famous

 PRO BOZO PUBLICO -- Support your local clown.

 MONAGE A TROIS -- I am three years old.

 FELIX NAVIDAD -- Our cat has a boat.

 HASTE CUISINE -- Fast French food

 VENI, VIDI, VICE -- I came, I saw, I partied.

 QUIP PRO QUO -- A fast retort

 MAZEL TON -- tons of luck

 APRES MOE LE DELUGE -- Larry and Curly got wet.

 PORTE-KOCHERE -- Sacramental wine

 ICH LIEBE RICH -- I'm really crazy about having dough.

 FUI GENERIS -- What's mine is mine.

 VISA LA FRANCE -- Don't leave your chateau without it.

 CA VA SANS DIRT -- And that's not gossip.

 MERCI RIEN -- Thanks for nothin'!

 AMICUS PURIAE -- Platonic friend

 L'ETAT, C'EST MOO -- I'm bossy around here.