You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. In which way I can assist you today?

USER: My name is Nicole Brown.

ASSISTANT: Good morning Brown.

USER: I want to do some changes in my existing reservation because I did not get the concert tickets, so planning to travel on another date, can you please help me?

ASSISTANT: Sure, I am happy to help you with that. Please wait a moment, I will check the existing reservation status.

USER: Sure.

ASSISTANT: Thank you for your patience.

USER: It's alright.

ASSISTANT: Sorry Brown, there is no reservation has found under your name to change it.

USER: It's ok, thank you.

ASSISTANT: Thank you for choosing us. Have a good day.

USER: Thank you.