You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Donald Young.

ASSISTANT: Donald, how can I assist you today?

USER: As I am feeling unwell, I would like to change my existing reservation to Dallas. Can you help me with this?

ASSISTANT: Sure, please wait for a while.

USER: Take your own time.

ASSISTANT: Sorry Donald, I did not find any reservation under your name in our database.

USER: Ok, not an issue. May be something went wrong while making the reservation. Thank you for providing information.

ASSISTANT: It's my pleasure, have a nice day.