You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: Thomas Anderson here. I would like to change existing my reservation due to some health issues, can you please help me in that?

ASSISTANT: sure, I will be helping out. Please wait a moment.

USER: Thank you. I will wait for your response.

ASSISTANT: There are no active reservation on your details.

USER: That's ok, no problem. Anyway thank you for the information.

ASSISTANT: Thank you for reaching us.