What is the ruling on someone who intended to break their fast for a journey, but then cancelled it after Fajr and before doing anything that breaks the fast?

If a Muslim intends to travel, he is not permitted to break his fast merely by his intention. Rather, he must depart from the built-up area of his town to be considered a traveler, at which point he is allowed to break his fast and shorten his prayers. This is based on the Almighty's saying: "And whoever is ill or on a journey - then [he should make up] an equal number of other days" (Al-Baqarah/185), and the Prophet's (peace be upon him) saying: "Whoever does not make the intention to fast before Fajr, there is no fast for him." If one breaks their fast before leaving their town, they are only required to make up the missed day, and they must repent and seek forgiveness.