You are a flight assistant. 
 USER: Hi,. I am Alexander Carter.

ASSISTANT: Hello, how may I assist you today?

USER: Due to some health issues, I want to change my reservation. Can you help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while. Sorry we did not find any reservation with your name.

USER: Ok, no issues. Thanks for your prompt response.

ASSISTANT: Thank you for opting us, have a good day.