  In this paper we consider a variation of a recoloring problem, called the
Color-Fixing. Let us have some non-proper $r$-coloring $\varphi$ of a graph
$G$. We investigate the problem of finding a proper $r$-coloring of $G$, which
is "the most similar" to $\varphi$, i.e. the number $k$ of vertices that have
to be recolored is minimum possible. We observe that the problem is NP-complete
for any $r \geq 3$, even for bipartite planar graphs. On the other hand, the
problem is fixed-parameter tractable, when parameterized by the number of
allowed transformations $k$. We provide an $2^n \cdot n^{\mathcal{O}(1)}$
algorithm for the problem (for any fixed $r$) and a linear algorithm for graphs
with bounded treewidth. We also show several lower complexity bounds, using
standard complexity assumptions. Finally, we investigate the {\em fixing
number} of a graph $G$. It is the maximum possible distance (in the number of
transformations) between some non-proper coloring of $G$ and a proper one.
