You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Meeting my friend on his birthday got postponed, will you help me to change my existing reservation?

ASSISTANT: Sure, we are glad to serve you.

USER: Thanks.

ASSISTANT: Can I have your name to proceed?

USER: My name is Anna Williams.

ASSISTANT: Ok, please wait a moment, let me check your reservation with us and let you know.

USER: Sure.

ASSISTANT: Thank you for holding on, sorry, no reservation found on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for availing us.