“Jumping” over a person’s position who is of higher rank
It sounds as though such a person is about to leapfrog over his superior and land a corporate position in which his erstwhile superior/boss has now become his subordinate or underling.
leapfrog: to go straight from a job or position that was lower in status than someone's to one that is higher than theirs (Macmillan Dictionary).
I would describe this as "leap-frogging."
"Leap-frog" is a childhood game.
- A boys' game in which one player places his hands upon the bent back or shoulders of another and leaps or vaults over him. Also, a jump or leap of this description. (OED)
Merriam-Webster has a better example of this metaphorical usage:
Skipping his last two years of high school, he leapfrogged his classmates and went to college.
I would simply say "I was promoted above my boss."
You can say the same thing for any promotion, really. "I was promoted above my co-workers" for a single step up. The reference to "my boss" implies that you've moved up two steps rather than just one, and that your former boss is now your subordinate.