This work investigates how education and training policies may facilitate occupational transitions. It proposes a methodology to estimate cognitive and task-based skill distances across occupation. It identifies the occupational transitions that can occur upon small (of up to 6 months), moderate (up to 1 year) or important (up to 3 years) (re)training spells. "Possible" transitions, i.e. transitions implying reasonable upskilling needs and similar knowledge areas, are distinguished from "acceptable" occupations, i.e. possible transitions entailing limited loss of human capital and income, if any. Possible and acceptable transitions exist for the quasi-totality of occupations, when up to one year of training is considered. Low-skilled occupations display fewer acceptable transitions and generally require higher cognitive or task-based skills. Transitions for many high-skilled occupations entail important wage decreases or skills excesses. Acceptable transitions for occupations at high-risk of automation are harder to find, and tend to require cognitive and task-based skills-related training.