How to remove samsung syncmaster 2243SN stand?

There's two or three stand options for that model, but from the last round of Samsungs I used with "simple stands", they were a PITA to remove; so I'll assume that's what you have.

The hollow connector shaft that goes from the round base to the monitor itself, is press fit (by the user during unpacking) onto a hinged piece that's attached to the monitor. Then the round base is screwed (with a thumb-screw) to the connector shaft.

Unscrew and remove the round base.

Look up into the connector shaft. There is probably two small plastic tabs accessible from inside the connector shaft. To release the shaft, both tabs need to be pushed apart (maybe inward?, it's been a while), and held out of the way while the shaft is wiggled off a millimeter or two at a time.

Again, it's a PITA, so expect plenty of fidgeting and wiggling to get both tabs released at the same time so that the connector piece can be pulled/wiggled/worked off of the monitor.

A couple small slot screw drivers can help with triggering/holding the tabs. Having a second pair of hands to pull while holding the tabs can help as well. :)