Calla Lily

A friend of mine has got some calla lily`s growing in her garden and has asked me if i would like some,but both of us don`t know how to divide them or the best time can anyone help

 

I think it's best to wait till the end of the summer now before she divides them, then when she gives you your bit, plant straight away and just wait, they will dye down for the winter, hope it's the hardy white ones we are talking about?