You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you help me to change the reservation which I had done recently?

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

USER: Ok, please check for the name Richard Johnson.

ASSISTANT: Ok, please give me a minute.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry, there is no reservation found with your name to change the details.

USER: That is ok, thank you for providing the information.

ASSISTANT: You are welcome. Thank you for choosing us.