text: Passage of Lines
  16-41. Close coordination between the passing and stationary force is crucial to successful execution of the
  rearward passage and subsequent transfer of responsibility. This requirement for close coordination is even
  more critical when the tactical situation results in a staggered or incremental rearward passage across an
  assigned area. Passing force commanders relinquish control of their subordinate elements remaining in
  contact at the time of the transfer of responsibility to stationary force commanders. Generally, stationary units
  assume control of their respective assigned areas forward of the BHL after two-thirds of rearward passing
  combat elements move through their passage points.
  PREPARING A REARWARD PASSAGE
  16-42. Rearward passing forces begin coordination with those stationary forces through which they are
  going to move after receiving their warning orders. The command posts of both forces involved move to a
  position where they can co-locate as part of the preparations for the rearward passage.
  16-43. The commanders of these forces coordinate the same details as those outlined for a forward passage
  of lines. If necessary, fire support assets from the stationary force occupy positions forward of their primary
  positions to give maximum coverage of forces to the rearward moving unit. The two staffs coordinate those
  control measures necessary to support retrograde operations and their associated rearward passage of lines.
  (See paragraphs 16-9 through 16-12 for a discussion of control measures.) These two commanders establish
  a probable time to initiate passage.
  EXECUTING A REARWARD PASSAGE
  16-44. Passing forces maintain command of their subordinate elements throughout their retrograde and
  rearward passage. The normal order of march in a rearward passage of lines is sustainment elements, main
  command post, functional and multifunctional support elements, tactical command post, and combat units.
  Passage points mark the locations where rearward passing forces come under the control of restrictions placed
  by stationary forces. If enemy forces continue to press their attacks, passing forces continue to control
  operations from the co-located command posts while stationary forces monitor and control the passage of
  lines in their assigned areas until battle handover occurs. Passing force command posts pass through the lines
  as soon as possible after the lead elements complete their passage. On passage of command, stationary forces
  assume control of ongoing operations.
  16-45. Stationary forces provide rearward passing forces with as much assistance as possible, just as they
  do during a forward passage of lines. The provision of indirect and direct fire support to passing forces by
  stationary forces is crucial for the success of these passages. This is especially important in covering the
  withdrawal of detachments left in contact during a delay. Stationary force fire support assets answer calls for
  fire from the passing force until battle handover occurs. The passing force’s fire support assets echelon
  rearward to provide continuous fire support for the passing force until it can successfully disengage.
  Stationary forces initiate and clear calls for all fires forward of their locations once passing forces transfer
  control operations to them. The same procedure applies to any direct support air and missile defense assets.
  16-46. Stationary forces ensure that passing forces are able to move through passage routes and lanes. They
  employ available engineer assets to maintain these routes and lanes for use by passing forces. Stationary
  force commanders shift these assets to close gaps in their obstacles and defensive positions once passing
  forces and their forward security elements disengage and withdraw through their forward security areas.