You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Andrew Davis.

ASSISTANT: How may I assist you today?

USER: I need your help in altering my existing reservation. Will you help me with this?

ASSISTANT: Sure, I am here to help you, please wait for a minute to check the reservation.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, I could not find any reservation with your name in our database.

USER: Ok, not an issue. May be something went wrong while booking the ticket previously.

ASSISTANT: Ok fine.

USER: Anyways, thank you for your time.

ASSISTANT: Welcome.