Q: Do you know of anything that would prohibit a church dedicated to the name of St. Paul to celebrate the patronal feast day on Conversion of St. Paul (January 25, 2021) instead of the Solemnity of Sts. Peter and Paul (June 29)?
A: I don’t know anything that would prohibit it because Paul is in the unusual situation of having two days. In truth, the default should probably be his dies natalis, June 29. But of course he shares that with Peter and has the Conversion all to himself.
I think a parish named St. Paul could make a case for claiming January 25. It would be stronger, though, if the parish were called The Conversion of Saint Paul, to make it clear.