Learn English – Opposite of smartwatch

I think principal might work for you. It's used fairly frequently to describe the primary people involved in things and the following is listed as one of the (chiefly legal) definitions:

a person who authorizes another, as an agent, to represent him or her.

Looking strictly at the Latin roots of concatenate:

concatenare, from Latin com- + catenare, to chain [MW]

com- is the Latin prefix meaning "together, with."

dis- is the Latin prefix meaning "apart."

(de- means "down or away from," so you can make the case for that as well.)

So: discatenate, or decatenate.

Edit: As I (and FF) noted in a comment, decatenate is used in biology/biochemistry to describe the unlinking of a chain of chemical elements.