American English Corrections

Making a Dialog or "Creating an Example Dialog"

I tried to make a dialog today.

W: What can I do for you?
M: Yes, I want to make a reservation for a flight to New York. or "I would like to make a reservation for a flight to New York." to sound more formal / professional. My parents would say "I want to make a reservation" since they just usually always speak informally. Hehehehe. A business man would speak more formally though, or at least they should. :)  
W: When do you want to leave for the trip? or "When would you like to leave for the trip?" to be more formal / professional sounding.
M: At 7 p.m today.
W: Do you want a round trip ticket? or "Would you like a round trip ticket?" to be more formal / professional sounding.
M: Yes, I want to come back next Monday. or "Yes, I would like to come back next Monday." to sound more formal / professional.

Making a dialog.

I tried to make a dialog today.

W: What can I do for you?
M: Yes, I want a reservation for a flight to New York.
W: When do you want to leave for a trip?
M: 7 p.m today.
W: Do you want a round ticket?
M: Yes, I want to come back next Monday.

This is good but it sounds a little unnatural. Most shop assistants are very, very polite. Here's how I would do it:

W: Hi, can I help you? / Hi, what can I do for you?
M: Yes, I'd like to book a flight to New York, please.
W: When would you like to leave?
M: 7 p.m today.
W: Would you like a return ticket?
M: Yes, I'd like to come back next Monday.

WELL DONE !!!

making a dialog.

I tried to make a dialogue today.

W: What can I do for you?
M: Yes, I want would like a reservation for a flight to New York.
W: When do you want would you like to leave for a the trip?
M: 7 p.m. today.
W: Do you want a round return ticket?
M: Yes, I want would like to come back next Monday.

Would like = formal version but not essential

Making a Dialog

I tried to make a dialog today.

W: What can I do for you?
M: I want to make a reservation for a flight to New York.
W: When do you want to leave?
M: 7 p.m today.
W: Do you want a round tiket?
M: Yes, I want to come back next Monday.