Here is a function that will work for numeric or string indices. Pass the array as first parameter, then the index to the element that needs to be moved and finally set the direction to -1 to move the element up and to 1 to move it down. Example: Move(['first'=>'Peter','second'=>'Paul','third'=>'Kate'],'second',-1) will move Paul up and Peter down.
function Move($a,$element,$direction)
{
$temp = [];
$index = 0;
foreach($a as $key=>$value)
{
$temp[$index++] = $key;
}
$index = array_search($element,$temp);
$newpos = $index+$direction;
if(isset($temp[$newpos]))
{
$value2 = $temp[$newpos];
$temp[$newpos]=$element;
$temp[$index]=$value2;
}
else
{
# move is not possible
return $a; # returns the array unchanged
}
$final = [];
foreach($temp as $next)
{
$final[$next]=$a[$next];
}
return $final;
}