2-78. Transitions mark a change of focus between phases or between the ongoing operation and execution of a branch or sequel. Shifting priorities among the offense, defense, and stability also involves transitions. Transitions require planning and preparation so the force can maintain the initiative and tempo of operations. Forces are vulnerable during transitions, so commanders establish clear conditions for their execution. Planning identifies potential transitions and accounts for them throughout execution. Effective commanders consider the time required to plan for and execute transitions. Assessment helps commanders measure progress toward such transitions and take appropriate actions to execute them.