You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you?

USER: I would like to change my reservation due to some issues with my Clint. Can you help me?

ASSISTANT: Ok, please provide your name so that I can check with your previous details?

USER: Myself Sandra Jones.

ASSISTANT: Sorry Sandra, there is no reservation found on your name.

USER: No problem. Thanks for helping me.

ASSISTANT: Thank you, have a great day.