OK - so I intend to answer my own question. 
This forum gives me the chance to address a [small] pet peeve. Sometimes you may want to respond to someone, but only "Quote" part of their post. If you click on "quote," your screen will look like this:

What if you want to "quote" only part of the original post? The answer is that you redact the unwanted parts, but you must maintain the open and close remarks which let the forum know that you are quoting material. See below:
