"Excuse me, goodbye."
Translation:Affedersin, güle güle.
It depends on who is leaving. The person leaving says hoşça kal, and the person staying says güle güle. Look at this scenario. You and a friend are hanging out, when suddenly your friend gets a call and finds out something has come up, and they have to leave. Since they are the one leaving, and you are staying, when they leave they would say "hoşça kal," and you would reply with "güle güle."
Hope this helps. :)
I can think of a few scenarios where you might have to excuse yourself from the conversation and say goodbye without leaving yourself. Most involve important phone calls or meetings. For example, if you're on hold with tech support and a co-worker stops by your desk to chat briefly before heading home, then someone comes on the line, and you have to tell your coworker, "Affedersin. Güle güle."