You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I am Dorothy Davis. I need to change my existing reservation as my plan to go for trekking for postponed. Can you help me?

ASSISTANT: Sure, Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: That's Ok, thanks for your response.

ASSISTANT: Thank you for reaching us.