Turn left and learn the rules.
If a Pivot or Blocker is not on the track when the jam-starting whistle blows ...
The Jammer becomes the Pivot or missing Blocker
The Pivot or Blocker can join the jam once there is a Lead Jammer in the jam
The Pivot or Blocker will not be permitted to join the jam in progress and no penalty will be issued
The Pivot or Blocker can join the jam once the pack has completed one full lap