Identify the root cause
As a sales manager working with a sales rep who is not meeting his/her goals, a common mistake is to leap to conclusions. There may be a variety of factors inside and outside of the office contributing to the slump.
Source: Sales trainer Steve Dodman
Discuss the slump with the salesperson and ask questions to get to the root cause. Is it something personal, such as a family matter, or professional, such as a lack of training?
With the root cause identified, you can begin to craft a plan to get the rep back on track.