If using updateboard within a clientside weapon it will automatically trigger to serverside and affect it for other players.
If you do this within a clientside NPC script however it will only be visible to you. The trouble here is that it's problematic to do dynamically in the same way you would cut a tiled bush, plus you'd then need a timer to restore it to its original tiles. For something like a one off change to a levels tiles within a quest it's quite easy.