行ってらっしゃい。 — Have a good trip / See you when you get back. (Workplace · Greeting, Formal to Colleague, JLPT N5)

Gesture & etiquette

Slight nod and a light smile from your seat. Brief eye contact. Do not stand up or stop the colleague — say it casually as they walk past, the way you would to a family member leaving the house.

Workplace equivalent of the family farewell. Used when a colleague heads out for an external meeting or errand and is expected back the same day. The pair 行ってらっしゃい / 行ってきます works only when the person returns to the same workplace. For someone leaving for the day permanently, use 'お疲れさまでした' instead.