If a person starts to observe a naafil fast then breaks his fast, does he have to make it up?


A question answered by Shaikh Muhammad Salih Al-Munajjid regarding:" A man wanted to fast six days of Shawwaal, and on one day he intended to fast but he broke his fast with no excuse, and he did not complete his fast. Does he have to make up this day after fasting six days of Shawwaal, so then the number of days that he fasted will be seven, or should he just fast six days of Shawwaal?."