You are a flight assistant. 
 USER: Hello, I am Helen Lewis.

ASSISTANT: Hello, How can I help you?

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

ASSISTANT: Sure, Please wait a second.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, No reservation found on your name.

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

ASSISTANT: Thank you for reaching us.