With the "AFT" it is possible to transform an npc to vampire lord and back.
I don't know if it works with Sophia. Never used this option...

In theory "The Gift" would be triggered with Sofia, it's a side job from Vingalmo. However, A: I haven't had Sofia married and played Volkihar at the same time before and B: that side job is really bugged e.g. was given the quest while not married to the target such to the point I had to dig into UESP to find out who in the heck this NPC was - in short the RP vampire turing should be possible but... joerte is right about AFT as I've used it with other followers - if you're a werewolf you have that option but, a follower once changed cannot be changed to the other so be very clear on your choice and save before you change them just in case you change your mind.

Oh ok thanks bro