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…
Yes, you can receive the Eucharist at Mass if you were at a Communion Service earlier in the day. However, since canon law refers to Mass as “the eucharistic celebration” (canon 899) the canon forbids the reverse (receiving at a communion service after having received at Mass).
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