You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Kenneth Garcia here. I would like to change my reservation due to some health issues,can you please help me out with that?

ASSISTANT: Sure, I will try to change your reservation, please wait for a while.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry Kenneth Garcia, I could not find any reservation with your name in our database.

USER: That's ok, no problem. Thank you for checking out.

ASSISTANT: Thanks for choosing us, have a great day ahead.