We describe PLANEXl, a plan executor for the Stanford Research Institute robot system. The problem-solving program STRIPS creates a plan consisting of a sequence of actions, and the PLANEXI program carries out the plan by executing the actions. PLANEXI is designed so that it executes only that portion of the plan necessary for completing the task, reexecutes any portion of the plan that has failed to achieve the desired results, and initiates replanning in situations where the plan can no longer be effective in completing the task. The scenario for an example plan execution is given.