In the previous Halachot we have explained that if one forgets to pray a certain prayer, the individual must compensate for the missed prayer by reciting the Amida of the next prayer twice, once for the current obligatory prayer and the second as a compensatory prayer for the prayer one missed.
The Poskim disagree whether or not the compensatory prayer must be recited immediately after the obligatory prayer. Some maintain that it must, i.e. that as soon as one concludes the Amida of the obligatory prayer, one must immediately begin the Amida once again for the compensatory prayer. Others write that that the two prayers do not need to be recited close together at all. Thus, according to the latter opinion, if one has forgotten to pray Arvit or if one has forgotten to mention “Ya’aleh Ve’Yavo” in the Arvit prayer of Chol Ha’Moed and the like (not the Rosh Chodesh Arvit prayer, though, for one does not repeat the Amida for omitting “Ya’aleh Ve’Yavo” from the Arvit prayer of Rosh Chodesh), one may pray Shacharit along with the congregation and following the Amida prayer one may recite “Ashrei”, “Uva Le’Zion”, conclude the entire prayer with the congregation, and only then recite the Amida prayer once again as the compensatory prayer.
Hagaon Harav David Yosef Shlit”a writes in his Halacha Berura that preferably, it is proper for one to pray the compensatory Amida prayer immediately following the obligatory Amida prayer without any interruption at all. One should not even interrupt between them to recite “Ashrei” and “Uva Le’Zion” and one should certainly not eat or take care of one’s business between them; rather, one should be quick to recite the compensatory prayer. Nevertheless, if one has interrupted between the prayers, whether one has done so by reciting “Ashrei” and “Uva Le’Zion” or by eating and the like, one must immediately stop what one is doing and recite the compensatory prayer. Before doing so though, one should stipulate a donated/voluntary prayer by thinking as follows: “If I am obligated to pray now, this prayer should be considered an obligatory prayer and if I am not obligated to pray, the following prayer is a donated prayer.”
Nevertheless, Maran Rabbeinu Ovadia Yosef zt”l writes that one who is praying Shacharit or Mincha along with the congregation and must recite a compensatory prayer may listen to the Chazzan’s repetition of the Amida and only afterwards begin the compensatory prayer, for the Chazzan’s repetition is not considered an interruption at all.
Our Sages only established the compensatory prayer for one who has not prayed inadvertently (or as a result of a situation beyond one’s control). However, if one has not prayed intentionally, one is not eligible to compensate this prayer.