You can only change your weigh-in up until the week has closed.  You cannot change any previous weeks weigh-in details.

Coming Soon:

We are adding a new function where, your team manager will be capable of changing your weigh-in for you and there will be full logging of all changes made by the manager so everyone has visibilty of any changes (your weigh in amounts will not be visible).  ETA - Nov 2007.