You are a flight assistant. 
 USER: Hi.

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

USER: Unfortunately, I would like to change my existing reservation due to some health issues, can you please help me in this intent?

ASSISTANT: Sure, I will help you with this.

USER: Thank you.

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

USER: Sure, my name is Charles Mitchell.

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

USER: That's fine.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your service.