You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How should I assist you today?

USER: Elizabeth Johnson here.

ASSISTANT: Nice to meet you Elizabeth.

USER: I want to change my existing reservation due to my grand father health, will you help me?

ASSISTANT: Sure, I am happy to help you. Please give me a moment.

USER: Sure.

ASSISTANT: Thank you for your patience. Sorry Elizabeth, there is no reservation has found under your name.

USER: Ok, thank you for your information.

ASSISTANT: Thank you for reaching us.

USER: Welcome.

ASSISTANT: Have a good day.