Cost Pools Parent
The Cost Pools Parent field is used to group organizations into a hierarchy for use in cost pools setup. This is an optional field (that is, if no value is supplied, the current Org will be treated as a root organization).
In the Organization List, this field will contain the org code of the current organization's Cost Pools Parent (should the current organization be configured to have a Cost Pools Parent).
Establish Cost Pools Org Hierarchy
Establishing a Cost Pools Parent Organization for the current organization is done on the Organization >> Edit >> Financials tab (Organization Hierarchies field).
When establishing a Cost Pools Parent Organization relationship, the values available to choose from will include all active Financial Organizations (plus the current Org selected should it have subsequently been made inactive) within the same Legal Entity excluding any child organizations (e.g. you cannot have organizations appear multiple times in the same organizations hierarchy).
There are no restrictions as to when you can change or remove an organization from participating in a Cost Pools Org hierarchy.
Org Hierarchy Report
Note you can view the complete Cost Pools Organization Hierarchy via the Reports >> Reference >> Organization Tree Views report.
Note regarding Auto-Complete Fields