PHP二维数组转一维数组问题

如何把下面1个数组转换成2个示例数组

//1
array(1) {
  [0] => array(12) {
    ["id"] => string(2) "11"
    ["time"] => string(10) "1679541441"
  }
}

//2
array(1) {
    ["id"] => string(2) "11"
    ["time"] => string(10) "1679541441"
}

直接用下标获取不就行了：

$a  = [
  0 => [
    "id" => "11",
    "time" => "1679541441"
  ]
];
print_r($a[0]);

img