You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Joshua Hernandez.

ASSISTANT: How may I assist you?

USER: I would like to change my reservation which was done earlier due to some personal issues, will you help me with that?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Ok, I will wait for your response.

ASSISTANT: Joshua, no reservation has been found on your name in our database.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.