Will a person be rewarded for intending to perform the four-rak'ah Fajr prayer on time, but then forgetting and not performing it, and can he make it up when he remembers?

If a Muslim intends to perform a supererogatory prayer, but something distracts him from it, he will be rewarded for his intention, and it is permissible for him to pray what he intended if he remembers it at a time when supererogatory prayers are permissible. As for the obligatory prayer, it must be performed at its appointed time, and if one fails to perform it due to forgetfulness, it must be made up when remembered. As for the Raghibah prayer, it is permissible to make it up before noon, but if noon passes, its time has elapsed.