mysql - how to convert time php so that it converts PT to CT -

i trying convert time default site time pt new york, want convert once pulling database heres code

date_default_timezone_set('america/los_angeles') ; $site_time = date("h:i:s",time()) ; 

this inserts time in pt

$insert_chat = mysqli_query($conn, "insert chat (time) values  '$site_time'" );  $select = mysqli_query($conn, "select time chat") ;   while ($row = mysqli_fetch_array($select)){       $chat_time = $row['time'] ; 

after pull pt time database convert new york ct

     date_default_timezone_set('america/new_york') ;       $user_time = date("h:i a",strtotime($chat_time)) ;       echo $user_time ;  

but when echo time still showing pt , doing wrong

a working solution using php standard objects:

$dt = new datetime(     '2017-01-01 09:00:00',     new datetimezone('america/los_angeles') ); $dt->settimezone(new datetimezone('america/new_york')); echo $dt->format("h:i a"); // 12:00 pm 

what happens in code $chat_time has no timezone associated it; it's string. calling date_default_timezone_set has no bearing on it. when call date formats string.