If you happen to accidentally miss taking your dose of Prozac for one day then nothing will usually happen but if you remember to take the Prozac even during the night of that same day then you can take the Prozac then.
I used to take Prozac myself and every once in awhile I would be so busy doing something else and then I'd forget to take my Prozac on some days.
Nothing happened to me and I just took the dose of Prozac the next day.