Esoteric science:  today is a result of yesterday and tomorrow will be a result of today. (what is done today will be done tomorrow). Any changes can be made only in ‘now’.  (One of the 48 Objective Laws of the Universe, under which humanity, in general, finds itself). So if by any chance anybody wants to change tomorrow, he/she has to do it ‘now’. By changing ‘now’ they will change tomorrow and by changing tomorrow they will change the past.