Q.Pre-Emergent
How soon can I re-seed after overusing Pre-Emergent ? Our lawn service contractor destroyed our grass and it needs to be re-seeded.
Thanks

It depends on what pre-emergent product /active ingredients was used and when.
A general answer is probably not this year for re-seeding to be safe. Consider using sod to re-establish your lawn and not seeds.
Are you sure it was a "pre-emergent" that destroyed the grass, or a combination pre and post emergent mix.?
You should find out the exact product(s) and contact the manufacturer information line on the product label. Or file a complaint or with the state pesticide regulation department or county agricultural commissioner. If you don't want to get the lawn service cited and fined, then make an inquiry with the county ag advisor.