You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your good name?

USER: I am Charles Rodriguez.

ASSISTANT: Nice to meet you Charles. How may I assist you today?

USER: I wanted to change my reservation due to my planned programme got postponed.

ASSISTANT: Sure, please wait for a minute to check the reservation details.

USER: Sure.

ASSISTANT: Sorry Charles, I cannot find any reservation with your details.

USER: Oh! It's OK. Thank you for your information.

ASSISTANT: It's my pleasure, thank you for approaching us.