Synonyms for Externalize:

n.

offer, materialize, render, personalize, voice, display, substantiate, give away, show, body forth, personify, surrender, incarnate, express yourself, manifest, make no secret of something, substitute, embody. externalize (noun)
project, exteriorise, exteriorize, objectify, externalise.

v.

embody (verb)
show, personalize.
externalize (verb)
substantiate, project, manifest, personify, exteriorize, objectify, incarnate, materialize.
manifest (verb)
embody, voice, display.
personify (verb)
body forth.

Other synonyms:

personalize. incarnate. embody. materialize, personify, manifest. substantiate. actualize
objectify.
come into being
materialize.
personify
body forth.
Other relevant words:
offer, embody, substantiate, personify, personalize, voice, manifest, show, render, body forth, display, materialize, substitute, incarnate, surrender.