You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you today?

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

ASSISTANT: Sure, I'll help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: Please let me know your name to check the reservation status.

USER: My name is Jonathan Taylor.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting. there is no active reservation have been found under your name in our database to amend it.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.