Solved
What is the best way to import List Purchase Leads without updating Lead fields of Leads already in our database?
We have run into the issue of importing a list of List Purchase Leads into a static list and some of those List Purchase Leads exist in our database and then the List Purchase Lead data overwrites/updates those existing Leads in our database. How can we make the import not update fields that already have an owner? We do not want to update/change those fields since we trust more what the Rep has for the Lead record rather than what the List Purchase says. We don't want to corrupt that existing Lead Data. Essentially we only want to import the List Purchase Leads if we know for a fact that they are not already in Marketo.