Salespeople who have “lost the fire” are salespeople who have lost sight of their sales goals, so you must help them see their future more clearly.
To create your plan, ask good questions, and really listen. Ask: Why are you selling for a living? What is it that you want, that you don’t currently have? Where do you want to be in 24-36 months? What motivates you?
For example, one salesperson may want to buy a house, another wants to join a golf/country club, a third wants your job. Three very different goals, but all could be achieved faster by exceeding sales quota.