how to delete element form 2D array in php

i have array look like bellow

我有阵列看起来像波纹管

Array
(
    [0] => Array
        (
            [REDUNDANT] => NO
            [FILE_NAME] => 51894a (2).pdf
        )
    [1] => Array
        (
            [REDUNDANT] => YES
            [FILE_NAME] => book (2).pdf
        )
    [2] => Array
        (
            [REDUNDANT] => YES
            [FILE_NAME] => samae (1).pdf
        )
    [3] => Array
        (
            [REDUNDANT] => NO
            [FILE_NAME] => aswss (1).pdf
        )        
)
A