Bumping. In the event a non-probationary employee is scheduled to be laid off and there exists a position in an equal or lower graded classification which the employee has previously held for the Employer in a competent manner, or if the regular duties of the position are a part of the normal requirements of the employee in his/her present position and which the employee can immediately perform in a competent manner, seniority shall prevail in permitting such employees to bump the least senior individual in such classification covered by this Agreement.