We want Harry to move from tech to advisor. Or advisor to the manager. Or tech to shop foreman. Etc. So, we have him work in the new role while maintaining the old one. While that can work, it rarely works great because it’s hard to be two things simultaneously. Instead, have him take on the new role 100% one day per week while doing nothing of the old position. When ready, move it to two days a week, etc. The odds are that everyone will like this better, and the process will take less time to complete.