Can. 917 A person who has already received the Most Holy Eucharist can receive it a second time on the same day only within the eucharistic celebration in which the person participates, without prejudice to the prescript of ⇒ can. 921, §2.
Actually the second communion there is during a “new day” (it is based on the midnight to midnight clock)…and so it would not have to be during the Mass one attends…it could be outside of Mass or say one is walking through a Church (like in Rome) and one is otherwise disposed (fasted etc)
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