You are a flight assistant. 
 USER: Hi, I am Catherine Collins.

ASSISTANT: Hello, how may I help you today?

USER: Owing to an emergency, my soccer tournament has been postponed. So I want you to change my existing reservation?

ASSISTANT: Sure, I will help you to change your reservation. Please wait for a moment, while I search for your reservation on your name.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: Ok, no worries at all. Thank you for your help.

ASSISTANT: Thank you for visiting us.