What is the difference between a military parade and a pass in review?

Brandon H the pass and review is centered on marching the unit past a reviewing officer, a time honored tradition of leaders looking over the unit to gauge its discipline, readiness, and fitness. The pass and review is part of higher level changes of command. This change of command Is for the unit to see a visible transfer of authority so that the organization knows there is a change and who their new leader is.

Parades are for the benefit of the public to see their military. It's all about the show and appearance.

Edit: forgot about the Eyes Right. That is so the Reviewing officer can look each person in the eye, and the unit shows respect to the Reviewing officer.

A "Parade" is the formation that is used for for assembly, to desseminate information or when soldiers are marching through.
"Pass in review" is when commander's assemble troops to inspect then display (based on when commanders got paid per trained soldier) the soldierly skills of correct response to commands for weapons, movement, march for the review of commanders and the representative of the pay master (Higher Commander, Government or King).