You are a flight assistant. 
 USER: Hi. I am Debra Garcia.

ASSISTANT: Hello, how can I serve you?

USER: I need to change my existing reservation as my sister coming to home after a 6 months. Can you serve me in this?

ASSISTANT: Sure, please wait a moment I will check and let you know.

USER: OK.

ASSISTANT: Thank you for waiting. Sorry, we did not found any reservation on your name.

USER: Ok, no problem at all. Thanks for your time with me.

ASSISTANT: Thank you for reaching us.