What do you call a person who conducts seminar workshops?
Solution 1:
Facilitator is sometimes used to describe someone who leads a seminar.
A facilitator is someone who helps a group of people understand their common objectives and assists them to plan to achieve them without taking a particular position in the discussion.
[Wikipedia]
Solution 2:
Coach, instructor or tutor. Will likely depend on what they want themselves to be called, and what kind of workshop it is.