I would like to sell 200 shares of NYSE stock quickly and easily. I
have never traded stock before. I live in the city of Philadelphia.

Do you own the stock?  If so, do you have the stock certificates?

If you have the stock certificate(s) and they have your name on them,
trot around to a stock broker (with the best form(s) of identification
you have:  passport, driver's license, etc. - if possible, one with a
photo) and ask then to sell them.
If the stocks are in an account in your name with a stockbroker (maybe
you inherited them, and that's why you have no experience), you should
be getting monthly statements, and there is probably the name and
phone number of the person who is your broker on the statement.  Call
him or her and ask to sell.  If he/she does not recognize you, the
person will suggest how you can identify yourself.

If you are in possession of stock certificates that are not issued in your name  
- maybe inherited and still in the name of the deceased -, then you
will have to  prove your legal ownership, and this is where I sign
off.
A researcher will need more details from you.
Good luck.

A Wire House (Online Brokerage Firm) will usually take far less
commission to sell the shares than a traditional brokerage firm.

I sold the stock on ETrade cheaply and easily. Thank you for the comments.