cancel, kill

Cancels an execution branch

concurrence
  sequence tag: 'blue'
  sequence
    cancel ref: 'blue'

You can drop the ref:

concurrence
  sequence tag: 'blue'
  sequence
    cancel 'blue'

It's also OK to use nids directly:

concurrence         # 0
  sequence          # 0_0
    # ...
  sequence          # 0_1
    cancel nid: '0_0'
      # or
    #cancel '0_0'

But it's kind of brittle compared to using tags.

kill

"kill" is equivalent to "cancel", but once called, cancel handlers are ignored, it cancels through.