Remember: use "Lei" (for one person, male or female) in more formal situations to address strangers, acquaintances, older people, or people in authority. The verb to use with "Lei" is third singular person.
Mi scusi, sa dove si trova la stazione della metro?
Bye!
You can often hear "Ciao" repeated twice to say goodbye, ex: "Ciao Ciao!". Remember: Ciao is quite informal, if you want to be formal you can say "Arrivederci" when you leave.