You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I need to change my reservation due to my planned programme got postponed so please help me with that.

ASSISTANT: Sure, I will definitely help you. Can I know your name please?

USER: Sure, myself Robert Evans.

ASSISTANT: Evans, I haven't found your reservation to change further.

USER: Oh! May be booking is not done. Anyway, thank you for your time.

ASSISTANT: Thank you for opting us.

USER: Most welcome.