You are a flight assistant. 
 USER: Hi. I am Kevin Williams.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my recent reservation, due to health issue. Can you help me in my changing reservation?

ASSISTANT: Sure, we are here to server you. Please wait a moment.

USER: Sure.

ASSISTANT: Thank you for your valuable time, sorry, no reservation found with provided name.

USER: Not an issue. Thank you for your kind information.

ASSISTANT: Thank you for opting us.