You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Unfortunately, I would like to change my existing reservation due to some problems, can you please help me in this intent?

ASSISTANT: I am happy to help you, can you please let me know your name?

USER: Sure, my name is Susan King.

ASSISTANT: King, please wait for sometime. I will get back to you.

USER: Ok, I will wait.

ASSISTANT: King, I have not found any reservation by your name in our database.

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

ASSISTANT: Thank you for contacting us and have a nice day.