Short answer: You can't, assuming you're asking whether you can respec like regular skills.
The limit for earning spec points is somewhere around 150, enough to fill every tree. With admiralty, doffing, featured episode rewards, and XP from other content, it doesn't take that long to do this. I made a new character for the AoY recruiting event last year and I think I had all the spec trees filled before the latest Anniversary Event, maybe even Christmas. So the specialties I actually use filled up well before that. You can switch your active specializations at any time and start investing points; all you lose is a bit of time.
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The limit for earning spec points is somewhere around 150, enough to fill every tree. With admiralty, doffing, featured episode rewards, and XP from other content, it doesn't take that long to do this. I made a new character for the AoY recruiting event last year and I think I had all the spec trees filled before the latest Anniversary Event, maybe even Christmas. So the specialties I actually use filled up well before that. You can switch your active specializations at any time and start investing points; all you lose is a bit of time.