1) Alter 2) Change 3) Modify 1) Hydrogenize 
• (v. t.) To hydrogenize.
(hi´dro-jәn-at″) to cause to combine with hydrogen; to reduce with hydrogen.
Hy'dro·gen·ate transitive verb [ imperfect & past participle Hydrogenated ; present participle & verbal noun Hydrogenating .] (Chemistry) To hydrogenize. 
[v] - combine or treat with or expose to hydrogen, esp. to add hydrogen to the molecule of (an unsaturated organic compound)
verb combine or treat with or expose to hydrogen; add hydrogen to the molecule of (an unsaturated organic compound)
to combine or treat with hydrogen, esp. to add hydrogen to the molecule of (an unsaturated organic compound).