"Dropping cases"

[andymckay]

If this is done before any data for the specified child has been inputted, the prior registration
should be deleted and replaced by the new one. However, if this is done any time after data has
been sent for the child, the prior registration and data should be archived, sorted by year, and
available for exporting.

No idea how to do that in the current config. Or what the second part means.