Explanation
To free up user licenses for new users, the administrator should deactivate the former employees user record.
This will prevent them from logging in and using Salesforce resources, but preserve their historical activities and data. Deleting or freezing user records will not release user licenses. References:
https://help.salesforce.com/s/articleView?id=sf.admin_usermgmt_licensing.htm&type=5

Explanation
A user with manager role above the agent can change ownership on multiple cases thatare owned by the agent or by users below the agent in the role hierarchy. A user with the System Administrator profile can change ownership on any case, regardless of the owner or role hierarchy. References:
https://help.salesforce.com/s/articleView?id=sf.case_change_owner.htm&type=5https://help.salesforce.com/s/art

Explanation
The User Licenses related list in Company Information shows the types of licenses that have been purchased for an org and how many are available or used. It also shows the expiration date of each license type if applicable. This information can help administrators plan for license purchases and manage user access.
Searching for license types in setup does not show how many licenses have been purchased or how many are available or used. User Management settings in setup does not show license information either, but rather settings related to user login, session, identity, etc. Usage-based entitlement related list in company information shows information about usage-based licenses such as API requests or sandboxes, but not user licenses. References:
https://help.salesforce.com/s/articleView?id=sf.users_understanding_license_types.htm&type=5