You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you at this moment?

USER: I want to change my existing reservation due to bad health issues, can you help me with that?

ASSISTANT: Sure, I am here to help you with this.

USER: Thank you.

ASSISTANT: Can you please provide your name to check your reservation status?

USER: Mark Hernandez here.

ASSISTANT: Mark Hernandez, there is no active reservation found under your name in our database.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for contacting us.