You will be lvl20 EP afterwards - so no you dont lose it.
As a non-pet sorc since 2016 the U46 Patch Notes sound like: "Those who do not wish to interact with the pet gameplay can now replace this skill lineeso as a whole."
The rank in the current campaign gets reset from max. 3 to 0. It does not affect skillpoints.
It's unclear if you want to change the alliance in a faction locked campaign or if you want to use a alliance change token to change the alliance of a char. The later may also reset some quests and have some side effects, but not regarding skillpoints or character level.