You are a flight assistant. 
 USER: Hello, I am Paul Jackson.

ASSISTANT: Hello, how can I help you?

USER: I need to change my exixting reservation, can you help me in changing my reservation?

ASSISTANT: Sure, Wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting. Unfortunately, we did not found any reservation.

USER: Ok, thank you for your response.

ASSISTANT: Thanks for contacting us.