How to unlink/delink person from application account

Summary

We have application account, to a person record was accidentally associated. We are trying to remove the references to that person, since this is a system account.

Content

We have application account, to which a person record was accidentally associated. We are trying to remove the references to that employee, since this is a system account used for scheduling processes.

The account was created without any link to person record. Due to an accidental load, a dummy person record was created and later that was assigned/attached to the system account.

We are trying to remove the reference to person and not sure how to do this.