text: Appendix A
  Passage of Lines
  A-31. A passage of lines occurs under two conditions. A forward
  passage of lines occurs when a unit passes through another unit’s
  positions while moving toward the enemy (ADP 3-90). A rearward
  passage of lines occurs when a unit passes through another unit’s
  positions while moving away from the enemy (ADP 3-90). Ideally, a
  passage of lines does not interfere with the conduct of the stationary
  unit’s operations. Figure A-17 shows the symbols for both a forward
  and a rearward passage of lines. The arrow goes in the direction the
  passing unit is moving. Figure A-17. Forward and
  rearward passage of lines
  Passage Point
  A-32. A passage point is a designated place where the passing units
  pass through the stationary unit. The location of this point is where
  the commander wants subordinate units physically to execute a passage
  of lines. Figure A-18 depicts the graphic control measure for
  PASSAGE POINT 7.
  Figure A-18. Passage point
  Phase Line
  A-33. A phase line is an easily identified feature in the operational area utilized for control and coordination
  of military operations (JP 3-09). A commander establishes PLs to control the maneuver of the units. PLs are
  not boundaries unless designated as such and do not establish any specific responsibilities between units,
  unless the operation order so specifies. When possible, commanders place them along easily recognizable
  terrain features—such as roads, railroad tracks, rivers, and ridgelines—to ensure easy identification. Units
  normally report crossing PLs, but do not halt unless specifically directed. Some PLs have additional
  designations for specific purposes, such as an LD or a PLD. Figure A-19 depicts five phase lines being used
  for an offensive operation.