You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you today?

USER: I want to change my reservation due to health problem, can you help me?

ASSISTANT: Sure, could you please mention your name for checking the details in our database.

USER: Myself Mary Harris.

ASSISTANT: Please wait a moment Mary Harris.

USER: Sure.

ASSISTANT: Sorry we couldn't find any reservation on your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching our service.