Good lord, how can a palm get root rot? I been growing palms for 10 years now and I never thought to look. I just figured that if the roots rotted the palm would die and I would start over. I am not sure about root rot, some palms dont want you to mess with the roots, others dont care. If I was you, I would make sure you have good drainage. You need to add alot of perlite and some mulch or something to break up the soil. Sounds like if its got root rot, there is way to much water sitting around where it shouldnt be. Does your pot have holes? I dont know what you would do with the root. I think I would just fix my dirt problem and stick it back in the pot. Leave it alone and see what happens.

Which palm has root rot?

It's one of the filifera. Maybe I should just start cutting into the dead roots until I start to see live ones? I know some palms don't like their roots disturbed, but I figure what have I got to lose. I think tomorrow I'll add more perlite.

If this palm pulls out of the soil easily it's done for.

Washingtonias are one of the palms that is most easily reute pruned. I would say prune all of the damaged roots away leaving only the healthy roots. My understanding is that when one does that to a washingtonia you are also supploed to remove all except for the newest fronds. DO it now we are suppsed to get a few days of 80s which should stimulate new root growth.

I had a palm that had root rot. I watered it too much.

Well it turns out the problem is worse than I thought. I pruned about half of the rootball away(all dead roots) they were sitting in mud. I also started to remove the oldest boots and I found an ant colony living under them eating the decomposing part of the trunk. There is a rotten black spot on the trunk. I guess I'll spray the entire palm including the rootball with fungicide, and then replant in a really dry, fast draining sand/cactus/perlite mixture and hope that the roots get more aeration and oxygen. I hope my other filifera isn't like this too.

Blast those ants with an incesticide also. Good luck.