Hello.
Hello, how may I help you at this moment?
I am David Clark, can you help me to change my reservation I did a week ago?
Sure, I will help you. Can I have a moment please? Thank you for Clark. Sorry, there is no reservation existing on your name.
That's ok, not a problem I will check my mails to know more about my reservation.
Thank you for reaching us, have a nice day.
Thank you for assisting me.
You are welcome.