I wanted to show the date store in DB in different format and in Greek language.
I post this to save some time for people that searching same problem solution.
Use this function to replace the date string from DB with your target language. Replace the Greek days and months strings.
If you need another date format you need to change date_format param following directions from https://www.w3schools.com/PHP/func_date_date.asp
function TranslateDate($stringDate) {
$MonthGR = array('Ιανουάριου', 'Φεβρουάριου', 'Μάρτιου', 'Απρίλιου', 'Μάϊου', 'Ιούνιου', 'Ιούλιου', 'Αυγούστου', 'Σεπτεμβρίου', 'Οκτωβρίου', 'Νοεμβρίου', 'Δεκεμβρίου');
$MonthEN = array('/January/', '/February/', '/March/', '/April/', '/May/', '/June/', '/July/', '/August/', '/September/', '/October/', '/November/', '/December/');
$DayGR = array('Δευτέρα', 'Τρίτη', 'Τετάρτη', 'Πέμπτη', 'Παρασκευή', 'Σάββατο', 'Κυριακή');
$DayEN = array('/Monday/', '/Tuesday/', '/Wednesday/', '/Thursday/', '/Friday/', '/Saturday/', '/Sunday/');
$hmera = preg_replace($MonthEN, $MonthGR, date_format(date_create($stringDate), 'l d F Y G:i '));
$hmera = preg_replace($DayEN, $DayGR, $hmera);
return $hmera;}