Synonyms for In relation to:

adj.

concerning (adjective)
regarding.
regarding (adjective)
with reference to, as to, with regard to, with respect to, in regard to.

n.

in relation to (noun)
in regard to, with reference to, related, regarding, vis-a-vis, related to, concerning, as to, with regard to, with respect to.

prep.

about (preposition)
regarding.

Other synonyms:

regarding
regarding.