How To Word A Downsizing Notice?

[Unregistered]

With the new year, I've decided to downsize. Mainly to get rid of two problem families, who happen to be the last two I enrolled. No solid contract breaking reasons... I've been a provider for nearly 10 years and am just tired of first time parent antics.
Does anyone have a nice letter for downsize termination? A bit worried one will retaliate, so need it as nice as possible.