This, usually called narrative report, describes state of project activities at the date of reporting. Periods of regular reporting vary from three months to six months and all planned activities should be described. If activity is still in implementation phase then current state should be reported and compared with projects timeline, weather it is in planned time or delayed. For finished activities just that fact should be reported. The activities that are late thorough explanation of the reasons for delay and plan for their execution should be presented.
Any delay in project activities changes timeline, influences on predefined milestones and dependencies between activities and results.