transubstantiate

1. To change (one substance) into another; transmute.
2. Christianity. To change the substance of (the Eucharistic bread and wine) into the body and blood of Jesus.

[Medieval Latin trānsubstantiāre, trānsubstantiāt- : Latin trāns-, trans- + Latin substantia, substance; see substance.]

verb

To change into a different form, substance, or state: convert, metamorphose, mutate, transfigure, transform, translate, transmogrify, transmute, transpose. See change/persist.

The verb has 2 meanings:

Meaning #1: change (the Eucharist bread and wine) into the body and blood of Chris; in Christian dogma

Meaning #2: change or alter in form, appearance, or nature
  Synonyms: transform, transmute