Every time I go to sign in someplace to cancel, the sign in takes me to another page. Neither the app nor the browser have any menu choices for canceling. So you have to look for a long time to figure that out. Google had a cancel and it produces a secret URL. But they have lots of options that look like it would cancel. Nope, nope. You can only add to them. And obviously, one of the choices would be to cancel.