You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I best serve you today?

USER:  I need to cancel my reservation due to some personal issues.So can you help me with cancellation of my reservation?

ASSISTANT: Let me know your name to check your reservation?

USER: I am Sandra Lewis.

ASSISTANT: I have checked in reservation list to cancel your ticket, but could not find any reservation with your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.