To change the blade on an MK Diamond tile saw: Ensure the saw is unplugged or turned off and disconnected from the power source. Remove the water tray to prevent any water spillage. Lock the blade shaft using the locking pin or button typically found on the saw. Using a wrench, turn the blade nut counterclockwise to loosen and remove it. Remove the old blade and replace it with the new one. Reattach the blade nut by turning it clockwise and tighten it securely while holding the locking pin or button. Replace the water tray and ensure everything is in place. Reconnect the saw to the power source.