"Not this time, but maybe next time we can do that"

How to tell your child no with out them developing a tantrum. This works a lot better than just telling you kid No. Being understanding and telling your kids that they will have another chance helps to avoid crying and tantrums. Trust me. When I tell my daughter no it hardly ever goes as smoothly as when my wife says it.  

Quote is from Clarice at http://www.simpleheartsblog.com