unset
должен делать свою работу как
<?php
$arr = [
"full_name" => "Prawn life",
"address_city_id" => "173",
"address_province_id" => "21",
"address_district_id" => "4",
"address_details" => "blah blah",
"address_line_2" => "line 2",
"address_postcode" => "40100",
"email" => "test@gmail.com",
"phone_number" => "12412455",
];
unset($arr['email']);
unset($arr['phone_number']);
var_dump($arr);
?>
выход
array(8) { ["full_name"]=> string(10) "Prawn life" ["address_city_id"]=> string(3) "173" ["address_province_id"]=> string(2) "21" ["address_district_id"]=> string(1) "4" ["address_details"]=> string(9) "blah blah" ["address_line_2"]=> string(6) "line 2" ["address_postcode"]=> string(5) "40100"}