my kosher dill pickles didn't seal. DO I have to empty and repack with reheated brine? Or can I just reprocess w/new lids?

Here's more info on both possible causes of incomplete seal (to avoid in future) and what to do now, with these pickles....re-process or store in fridge/freezer.
https://www.thespruceeats.com/how-to-reprocess-unsealed-canning-jars-1388316
https://www.freshpreserving.com/waterbath-canning.html

Reprocessing pickles isn't an ideal thing, especially for cucumber pickles. That second cooking tends to make them go pretty soggy. What to do next kind of depends on how many jars you have that failed to seal. If you can, the best solution would be to store them in the refrigerator- where they will last several months. You could simply remove the old seals, make sure of your headspace, put on new seals and reprocess. Just be aware that they are likely to suffer as a result. You might be able to counter this a bit by using a product called Pickle Crisp- which is pure calcium chloride. It helps prevent pickles going soggy in the first place, and I use it from the start. If you didn't, adding it now won't restore their crispness, but it will help stop them getting any worse.