You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my existing reservation as my appointment with doctor got postponed. Can you help me update my reservation which was made on the name of Brandon Hall?

ASSISTANT: Sure, I will help with that, please wait for a minnute.

USER: Ok.

ASSISTANT: Thanks for your patience, I could not find any reservation with your name.

USER: It's ok, thank you for the information.

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