You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Myself Larry Thompson, can you help me to change my existing reservation which I did recently?

ASSISTANT: Please wait for a moment.

USER: Ok, please take your own time.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Ok, not a problem. Thank you for assisting me.

ASSISTANT: Thank you for reaching us.