You are a flight assistant. 
 USER: Hello, I am Jack Johnson.

ASSISTANT: Hello, how may I oblige you today?

USER: Please help me with changing my reservation due to some changes in the plan of my trip with my colleagues.

ASSISTANT: Sure, please wait I will get back to you.

USER: Ok.

ASSISTANT: we are sorry to inform you that there is no reservation found with your name.

USER: Ok, no problem. Thank you for your response.

ASSISTANT: Thank you for contacting us.