You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I support you?

USER: I am Karen Evans. I need to change my existing reservation, as my scheduled football match got postponed due to bad weather. Can you help me in my changing reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Just wait a moment, I will check your details and let you know the status.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. Sorry to say you that there is no reservation exist on your name to proceed further.

USER: Not an issue. Than you for your response.

ASSISTANT: Thank you for choosing our service.