  We study the time evolution of the Casimir-Polder force acting on a neutral
atom in front of a perfectly conducting plate, when the system starts its
unitary evolution from a partially dressed state. We solve the Heisenberg
equations for both atomic and field quantum operators, exploiting a series
expansion with respect to the electric charge and an iterative technique. After
discussing the behaviour of the time-dependent force on an initially
partially-dressed atom, we analyze a possible experimental scheme to prepare
the partially dressed state and the observability of this new dynamical effect.
