You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What service do you need from our agency?

USER: I would like to change my existing reservation, could you please help me?

ASSISTANT: Sure, I will help you to change the ticket details.

USER: Thank you.

ASSISTANT: Could you please mention your respective name?

USER: My name is Joshua Clark.

ASSISTANT: Ok, please give me a couple of seconds to check the ticket status.

USER: Sure, I will wait for your response.

ASSISTANT: I have not found any active reservation with your name in our system data to change the ticket details. Sorry for the trouble.

USER: No issues. Thank you for checking.

ASSISTANT: That's my pleasure. Thank you for reaching us.