You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. What help that you need from us?

USER: Donna Jones here. Can you change my reservation because suddenly I have change my plans?

ASSISTANT: Sure, I can help you. Please wait. Thank you for waiting.

USER: Sure.

ASSISTANT: I could not found your previous ticket booking to modify it. Thank you for approaching us.

USER: It's ok. Thank you for your time.

ASSISTANT: Most welcome.