Before leaving is "avant de partir" in French.
Tu sortirs
Well, the simple translation for "(they) are leaving" is "(ils) laissent" or "(ils) quittent".
Je pars demain.
The word "before" in French is "avant."
Je vous quitte
'Je pars' means 'I'm leaving' (present tense). 'Tu pars' means 'you're leaving' (present tense).
je m'en vais dans sept jours
The day before yesterday in French is "avant-hier."
The same as before station.
give a tip and say thank you
c'est déjà arrivé
Bon apetit