Checked this with one of my vampires, Adriana Sheffield. Adriana is friends with Clara Bjergsen who happened to be in the neighborhood. Offer to Turn was not on the Friendly menu the first time I checked, so I sent Adriana over to Clara and started talking. Clara was uncomfortable because it was raining, so Adriana asked to see Clara's cold weather outfit. After changing clothes, Clara was no longer uncomfortable, the conversation had reached Pleasant, and Offer to Turn was back on the Friendly menu. I then checked several other sims that are Adriana's friends and acquaintances. Offer to Turn was available on all of the other sims I checked, including another Uncomfortable sim. I don't know why Clara was different.
I would suggest that you just do a bit more relationship building with the Sims you would like to turn.
