Er, not too sure what you're asking here. If you mean a fat client where all
of the business logic is included in the front-end app which is installed on
each user's PC as opposed to a thin client where only the GUI itself is
included in the front-end app and the business logic is wrapped in a middle
tier installed on a server, then you do just that. Write all of your
business logic in the front-end app and distribute it to each user's
desktop.
However, I suspect this probably isn't what you're really asking, so can you
be a bit more specific...?