How do you encourage deletion of something without putting the user off?

Scenario: A manager has access to her team members data on an internal system. She also has access to certain team members that have since moved to another role or under another manager.

We want the managers to keep their employee roster up to date so it would be helpful if these managers "deleted" people they no longer are responsible for.

Through testing I received feedback that this remove feature was ignored because they don't want to mess up the database. The problem is the database is a mess because we have duplicates and crossed wires, so we need the managers to use this remove feature. So my question is how can I improve this component to actively encourage data cleansing?