You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: My name is Jennifer Green. Owing to emergency, I need to change my existing reservation. Please help me with that.

ASSISTANT: Please, wait for a while.

USER: Sure.

ASSISTANT: Sorry, no active reservation found on your name in our data base.

USER: No problem, thanks for your information.

ASSISTANT: Welcome, thank you for reaching us.

USER: Most Welcome.