You can reassign licenses to another user in multiple ways based on your requirement.
To reassign licenses assigned as a manager or administrator, go to Setup > Users. Select the Managed Licenses tab, and then select Change License Management. Select the required licenses and the new user.
As a regular ALM user, you can also change the ownership of specific licenses by changing the user assigned in the Managed by field from the License tab. To add this field to the License page, click Options > Add/ Remove columns and select Managed by.