You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I would like to change my existing reservation as my date of joining got postponed. Can you help me with that?

ASSISTANT: Sure, Can I know your name please?

USER: Patricia Green is my name.

ASSISTANT: Please give me a minute, I will check with the details in the reservation list.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: Ok, thank you for your response.

ASSISTANT: Have a good day.