You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, thank you for using chat service. How can we help you today?

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

ASSISTANT: I feel happy to help you with your issue. May I know your name to check with the reservation status?

USER: Sure, I am Melissa Hall.

ASSISTANT: Please allow me 2-3 minutes while I check with the reservation status.

USER: Ok, I will wait for your response.

ASSISTANT: Thank you for waiting,  Melissa Hall. Melissa Hall, regret to inform that there is no active reservation found under your name to amend.

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

ASSISTANT: Thank you for reaching our chat service.