›[I]to learn new skills, so that you can do a different job: Older people may not have the time or finances to retrain.David used to work in the financial sector but retrained as a lawyer.retrain to become sthHe's currently retraining to become a plumber.
›[T]to teach someone new skills, so that they can do a different job: Existing staff were retrained, and there were no job losses.retrain staff/workers/employees (to do sth)The airline has promised to retrain its staff to handle disabled people better.