Exam 1z0-750 topic 1 question 19 discussion

Robert has a form page, Page 5, on the EMP table. He has defined two validations.
Validation 1 checks that P5_MGR is not null.
Validation 2 checks that the employee selected in P5_MGR has a job of PRESIDENT or MANAGER.
How can Robert prevent the employee job validation (Validation 2) from firing when the P5_MGR is NOT NULL validation (Validation 1) has failed?