Can you miss Mass to go to a family reunion?

When attending a family reunion, is it a mortal sin to miss Sunday Mass?

Missing Mass for a frivolous reason is grave matter. Treating a family reunion as more important than Mass certainly could qualify, depending on the individual circumstances. If you are going to the trouble to plan to go to a family reunion, surely you can do some research now to find a local church for Sunday Mass. Think of the positive example you’ll be setting for your family.

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