[This was partially inspired by this excellent article that I read Saturday morning.]
I manage two teams. One of them has been through a lot of changes in the last 12 months, basically taking a rather sharp turn in responsibilities and day to day work. This was always the plan because I believed that there was no better team to take over this particular process than ours, but when it came down to actually implement the changes clearly it was not what some members of the team had signed up for.
One day recently one of our strongest team members told me she wanted to move to another team.
I know for a fact that there are managers in this world who would take this poorly. Best case scenario they wonder how the team member is going to be replaced and how it's going to affect the team members that remain. Certain other managers would worry about how this is going to reflect on them as a manager if one of their team members wants to move to another team.
The absolute worst response you could get from a manager is "no, I like you where you are" because this openly tells the team member that there's nowhere for them to grow in your organization. They would be better off finding a new job if they want something new, because there's nothing for them here but more of the same.
Then there's the manager that says "hell yeah, how can I help?". I'm very glad and very lucky to be in this camp and to be able to contribute to others growing their careers, even if it's through nothing more than encouragement.
Be a booster. Be a leader, not an anchor.