You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I would like to change my existing reservation, due to sudden demise of my grand father. Can you please help me?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please let me know your name to check the reservation list.

USER: My name is Robert Taylor.

ASSISTANT: Ok, please wait a moment.

USER: Sure, take your own time.

ASSISTANT: Thank you for your waiting, sorry to inform you that there is no reservation found by this name.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for approaching us.