MySQLcase When Then END in comparison

 Below is an example to use case When Then END in comparison in MySQL:
 (CASE WHEN stakeholders.Action = 'New' AND stakeholders.InitialHireDate IS NOT NULL
                                                        AND stakeholders.InitialHireDate < (
                                                        CASE WHEN contract.SEApptStartDate IS NULL THEN                 terms_contract_lut.SEApptStartDate
                                                         ELSE contract.SEApptStartDate
                                                        END
                                                        ) THEN  'REH' ELSE  UPPER(stakeholders.Action)
                                                        END) AS Action,
                                                        (CASE WHEN stakeholders.Action = 'New' AND stakeholders.InitialHireDate IS NOT NULL
                                                        AND stakeholders.InitialHireDate < (
                                                        CASE WHEN contract.SEApptStartDate IS NULL THEN terms_contract_lut.SEApptStartDate
                                                         ELSE contract.SEApptStartDate
                                                        END
                                                        ) THEN  'REH' ELSE  UPPER(stakeholders.Action)
                                                        END) AS ActionReason,