Sometimes it happens that you have been in a leadership position and then you're not. So then what? It kind of depends on why you no longer have your title...
Perhaps you are moving on to another leadership role. Yay, you! Your job is to gracefully welcome the new leader as you move into your new position. You also need to let your team know how much you have valued them, and what a great asset they will be for the new leader. Be gracious and don't burn any bridges.
Maybe you are retiring. This brings about many life changes. Try to focus on being able to devote your time only to those things that bring you joy. Yes, you may feel some loss. After all, your leadership title may have defined you for a very long time. But think of the possibilities! You have so many new opportunities open to you.
Maybe you "lost" your leadership title. Sure you can sit and wallow and blame this or that, but what does that get you? You need to decide if you really want your leadership title back - enough to go do the things that got you there to begin with. Are you willing to be a leader, even without a title? Then the question is: "Are you a leader in title or action?"