Check your security settings and make sure "Allow widgets" or something similar is enabled, then unblank the screen, leave it locked but press and hold the widget then drag it to the trash after it changes (you will know). If it won't let you, it might be the only widget, try swiping to the right and get the + symbol and add a new widget (clock or something), then swipe over to the calendar widget and remove it. I don't know why, but sometimes I have had issues removing a widget if it is the last one, and other times not.Didn't work for me, nothing happened on long holding the widget. I have a Google Nexus 5 (vanilla android) running Kit Kat 4.4.4.