Presume you mean via sql?
Manager is obtained via table per_assignment_supervisors_f.
Smple query below for an Emps manager
If you want the manager's manager - you just need to add the relevent tables again and do required joins.
(or could also do a hierarchical level query)

select
ppf.person_number,
ppfsup.person_number sup_person_number
from
per_all_people_f ppf,
per_all_assignments_f paf,
per_assignment_supervisors_f pas,
per_all_people_f ppfsup
where sysdate between ppf.effective_start_date and ppf.effective_end_date
and ppf.person_id = paf.person_id
and paf.assignment_type = 'E'
and sysdate between paf.effective_start_date and paf.effective_end_date
and paf.assignment_id = pas.assignment_id
and sysdate between pas.effective_start_date and pas.effective_end_date
and pas.manager_id = ppfsup.person_id
and pas.manager_type = 'LINE_MANAGER'
and sysdate between ppfsup.effective_start_date and ppfsup.effective_end_date

Did you check the learning assignment records table? Please check if below helps:

https://fusionhcmconsulting.com/2021/10/bip-query-to-extract-learner-completion-details/

Thanks.