Give and Take
It's never easy to take something away from a person. It could be pulling certain responsibilities from a team member, informing someone their idea has been shot down, or admitting there is no place for their suggestion. At the core, it's rejection, and that's always tough to swallow.
While your position may require you to take something from a volunteer or team member, you have the power to lessen the blow. You may need to take "X", but what can you give in return? An alternative venue or outlet for their creativity, a different responsibility with which they can excel?
Usually finding an alternative creates more work for you, the leader. It's above the call of duty and isn't required. But, if you're able to give more than you take away, that person's pride can stay intact. Honor a person, even in rejection, and you will be blessed in return.