Russian goodbyes
Good for both cases. formal and informal goodbyes.
The following phrases you can use both in formal and informal situations:
До встре́чи!
[da vstryé-chee]
Untill next time!
До за́втра!
[da závt-ra]
See you tomorrow!
Мне пора́.
[mnye pa-rá]
I have to go.