It would be best to wait until fall when the lily foliage has ripened. That's not to say you can't do it now but they are feeding the bulbs for next year's bloom right now and if you can't get a good shovelful of soil with the bulbs and you disturb the roots you risk losing bloom next year. Unless it's imperative you move them now I would wait until fall if they were mine.

Thank you, hostaholic - I will wait till fall.