transesterification
noun
trans·es·ter·i·fi·ca·tion
| \ ˌtran(t)s-e-ˌster-ə-fə-ˈkā-shən, tranz-
\
\
Medical Definition of transesterification
: a reversible reaction in which one ester is converted into another (as by interchange of ester groups with an alcohol in the presence of a base)