Linear second order PDE with constant coefficients

Question

I am doing this mathematical problem $c*G_{vv}+ d*G_{u} + e*G_{v} +f*G=0$, where $c, d, e$ and $f$- are constant coefficients. I already know that this is second order PDE and we classify it by looking at $\Delta= b^{2}-4*a*c=0$ since Coefficients $a=b=0$, which makes it a parabolic type of a PDE. The problem i am having is reducing this PDE to a canonical form. Can you help on how I can choose my characteristics in this case. Thanks in advance.