how do I remove the pole from the 11ft costco umbrella

If your umbrella stand is also Costco, its pole holder should screw onto the base. I would be tempted to remove the holding screws, then unscrew the metal pole holder from the base, lay the umbrella on a sturdy desk and then tap the holder off the wooden pole with a hammer. Tap is of course a relative term. Sometimes "whack" is more appropriate for the situation but the idea is to use as little force as possible to remove the holder without damaging its walls by applying hammer to the top of the pipe. Perhaps with the help of a large flat head screwdriver or a similar implement.