Have a nice day! Buona giornata!

Have a nice day!
Say hello to Maria! Give my kind regards to Maria!
Have a nice day!
Have a nice evening!
Have a nice weekend!
(For) you too!
Have a nice journey! Have a pleasant journey! Have a nice trip!
Have a safe flight!
Have a nice holiday! Have a lovely vacation!
Have fun! Have a nice time!
Enjoy your stay!
Good luck!
Buona giornata!
Saluta Maria! Fai i miei cordiali saluti a Maria!
Buona giornata!
Buon weekend! / Buon fine settimana!
Anche a te!
Buon viaggio!
Buon volo!
Buone vacanze (ferie)!
Goditi il tuo soggiorno!
Buona fortuna!