depends what you have your schedule setting set to, you can have cleaner planner to schedule from date actually cleaned or from the date its actually due.
So if its set from date actually cleaned and you did a job scheduled for 2 days time (the 20th) and did it today it would automatically reschedule from todays date (18th).
If you did the same as above but had the setting set to date actually due and did it today (the 18th) it would still reschedule the job from the date its due in 2 days time (20th).
think that makes sense
paul