Hey Jon, great question! Using conditional formulas would be best for this, here's a quick video if needed - https://www.clay.com/learn/how-to-use-ai-formulasHowever, I would pair that with a lookup integration to find out if a person already exists within the same table or elsewhere before enriching them. If the lookup returns true as in there's a match somewhere else, then you can ask the formula to check for that and not run.
If you're using the Find People function from the screenshot below, and importing to an existing table, it should be checking for duplicates already and removing