"Au revoir" means "goodbye" in French. You may simply reply "au revoir" in turn, or say "à bientôt" (see you soon) or "à la semaine prochaine / à l'année prochaine" (see you next week/ see you next year).
example of a replied farewell letter....
Re: Farewell
It is with a heavy heart that I am writing this letter to you. Today is my last day at work and I shall miss all of you. You have been great staff at the Service Department; I sincerely thank you for your great support to me during my tenure with you. You have cooperated well with me to make this Service Department of high reputation.
I am moving on with my career. I hope that each of you will continue to give your best to further the interest of this company while you remain in its employment.
Do your best to uphold the good name of this Service Department and Company. I wish each of you the best in your future undertakings.
With kind regards,
au revoir
Au revoir les enfants was created on 1987-08-29.
Au Revoir pronounced "o revoir" source: I take french, third year
Goodbye and see (or talk to) you tomorrow
au revoir
au revoir
It is pronounced "oh reh-vwah."
Au revoir means "goodbye" in French.
"D'accord, au revoir" means "OK, bye".
The duration of Au Revoir Taipei is 1.42 hours.
The duration of Au Revoir Shanghai is 2700.0 seconds.
Au revoir! in French is "Goodbye!" in English.
That is usually "Adiuex" or "Au revoir"
Au Revoir Taipei was created on 2010-02-14.
The duration of Au revoir les enfants is 1.73 hours.
The correct spelling of goodbye in French is "au revoir."
Au revoir les enfants was created on 1987-08-29.