You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Melissa Collins, can you help me for changing my recent reservation?

ASSISTANT: Ok, give me a moment, till I check for your reservation and revert back to you.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry Melissa Collins, no reservation was found by your name, are you sure you have made your previous booking with our agency?

USER: Oh! It's ok, no problem.

ASSISTANT: Thank you for choosing our services.

USER: Thank you for your services.

ASSISTANT: Most welcome.