Basic multivariate Factorization type question

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I came across this polynomial $$ x^2 - 2kxy + ky^2 +d; \, k>0 $$ in some of my work and was wondering if there was a trick to coercing/factoring it into a polynomial of the form $$ (x-x_0)^2-(y-y_0)^2+r $$ for some $x_0,y_0,r \in \mathbb{R}$. I was thinking a completing the square type approach but embarrassingly enough I'm stumped. All help is appreciated. Thanks.