Why transition now? You’re through the part of pet conjurer that sucks. From about level 40-50 you should have the skill points and devotions available to make the Conjurer’s pets not shit and from about level 70 or so, Conjurer isn’t that much slower than the Necro based pet builds and it’s tankier.
As for Vitality caster, there’s this guide by Nery that should help you to swap. Be aware that Conjurer is a DoT Vitality Caster though. You throw out a bunch of DoTs and then wait for them to kill things and you hope that the leech is enough to keep you alive while they die (it usually is).
I recently did a run through with both a pet and vitality caster Conjurer and I really wasn’t impressed. I’d strongly recommend a different mastery combination if you’re not going to play pets. Before you throw it all away though, maybe post a grimtools link so that people can help you fix the Conjurer? It honestly should be fine by that level. Not great, but fine.