  To study violation of CP, T and/or CPT symmetries in the $K^0-\bar{K^0}$
systems, one has to parametrize the relevant mixing parameters and decay
amplitudes in such a way that each parameter represents violation of these
symmetries in a well-defined way. Parametrization is of course not unique and
is always subject to phase ambiguities. We discuss these problems with freedom
associated with rephasing of final (or intermediate) as well as initial states
taken into account. We present a fully rephasing-invariant parametrization and
a particular rephasing-dependent parametrization, and give a couple of comments
related to these and other possible parametrizations.
