Crunch objects usually keep themselves in sync with the server when you manipulate them, but sometimes they can drift. Maybe someone else has modified the dataset you're working on, or maybe you have modified a variable outside of the context of its dataset. refresh() allows you to get back in sync.
# S4 method for CrunchDataset
refresh(x)# S4 method for ShojiObject
refresh(x)
# S4 method for CrunchVariable
refresh(x)
pretty much any Crunch object
a new version of x