You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. What service do you expect from us?

USER: I have to change my father's reservation because my sister's health is not well. Can you please help me?

ASSISTANT: Sure, I will help you.

USER: Thank you very much.

ASSISTANT: Can you please provide me your father's name to check the reservation?

USER: Sure, his name is Barbara Parker.

ASSISTANT: Sorry, there is no reservation found on your father's name Barbara Parker.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for reaching us.