As long as the very center is okay, it should recover with time.

That is a LOT of frost damage. Apparently you're not in zone 10b, after all. Zone 10b means that low temps never go below 35°F. Were that true, your A. attenuata would not currently be hovering on the verge of death. My guess is that the core will drop off, signaling meristem death, within the next week or so, but you may get lucky. Even if it lives, it's going to be pretty hideous for awhile. A. attenuata is one of the most tender Agaves out there. Prolonged exposure to 30°F is pretty much a death sentence. Good luck.

Thank you both. I checked the center and it's very firm. Checked on my hardiness zone and it's actually 10a. This happened 2 weeks ago when the temp dropped to 40 with 50mph wind. The browning edges on the leaves are due to mishandling when I first got the plant. The dents on the leaves are the result from a light frost. I should have move the plant to a warmer spot given that the attenuata is the most sensitive of all the agave to low temps.

I'm sure the core is firm. That doesn't mean it's alive. It would only go soft if it rotted from over-watering. Once again, that is not light frost damage. That is severe frost damage.

If the main stem is damaged beyond redemption maybe try cutting it off with a sterile knife till good healthy tissue is reached, often attenuatas will regenerate from the base and throw out new pups. My regular green one developed a unhealthy top after cold damage last year, I’ve cut it off and now have several pups growing happily from the severed base. It lives in an unheated greenhouse here in the U.K. with temps as low as -8C so far and the only extra protection is from a thin horticultural fleece thrown over it and all my other plants in there.

Gill