1) Whatever she does, do not take it both away at the same time.
2) Do not do it at growth-spurts or when he is hitting developmental milestones. Because, this will be harder and kids naturally get sleep tweaks at growth-spurts and change a lot cognitively at developmental changes and stages.
Time it, wisely.
3) Have a 'substitute' in place or planned. Like a Lovey for him etc., to sleep with instead.
4) Have a consistent sleep routine per bedtime or nap time.
5) Don't make it a whole big deal out of it.... sometimes that will make the child cling to it more and think something is 'wrong'....
6) again, do it one at a time.