You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Dorothy Phillips. Can  you please help me in changing my flight ticket modification?

ASSISTANT: , please wait for a while I will check your status of reservation whether it's existed or.

USER: Sure, take your time. I will wait for your response.

ASSISTANT: Thanks for your time, there is no reservation found with the name Dorothy Phillips.

USER: Ok, no problem with that one, thank you for your immediate response.

ASSISTANT: Welcome, have a good day.