PHP - Date From Url To Database

Hi people I have some code to retireve dates from a database, see below.

The issue is i can not find a way to change the output to d,m,Y instead of what the data comes back from database.

Any help with this would be much appriciated.

The transaction date is getting the invoice date created back as 2020-04-01 etc, but how to swap this code?, I dont think i can do it within the array.

$statement_transactions = array();
        $client_total_balance = $client_opening_balance;
        foreach ($client_invoices as $invoice_entry) {

        $transaction = [
                'transaction_type'          => self::TRANSACTION_TYPE_INVOICE,
                'transaction_date'          => $invoice_entry->invoice_date_created,
                'transaction_amount'        => $invoice_entry->invoice_total,
                'invoice_id'                => $invoice_entry->invoice_id,
                'client_id'                 => $invoice_entry->client_id,
                'user_company'              => $invoice_entry->user_company,
                'invoice_amount_id'         => $invoice_entry->invoice_amount_id,
                'invoice_item_subtotal'     => $invoice_entry->invoice_item_subtotal,
                'invoice_item_tax_total'    => $invoice_entry->invoice_item_tax_total,
                'invoice_total'             => $invoice_entry->invoice_total,
                'invoice_sign'              => $invoice_entry->invoice_sign,
                'invoice_status_id'         => $invoice_entry->invoice_status_id,
                'invoice_date_created'      => $invoice_entry->invoice_date_created,
                'invoice_time_created'      => $invoice_entry->invoice_time_created,
                'invoice_number'            => $invoice_entry->invoice_number,
            ];

            $client_total_balance += $invoice_entry->invoice_total;

            $statement_transactions[] = $transaction;

        }

<?php

//if form has been submitted process it
if(isset($_POST['submit'])){

		$_POST = array_map( 'stripslashes', $_POST );

		//collect form data
		extract($_POST);

		//very basic validation
		if($title ==''){
			$error[] = 'Please enter the title.';
		}


		if(!isset($error)){

			try {

				//insert into database
				$stmt = $handler->prepare('INSERT INTO event_calendar (title,event_date,description) VALUES (:title, :description, :event_date)') ;
				$stmt->execute(array(
					':title' => $title,
					':description' => $description,
					':event_date' => date('Y-m-d')
				));

				//redirect to index page
				header('Location: index.php?action=added');
				exit;

			} catch(PDOException $e) {
			    echo $e->getMessage();
			}

		}

	}

	//check for any errors
	if(isset($error)){
		foreach($error as $error){
			echo '<p class="error">'.$error.'</p>';
		}
	}
	?>
	<form action='' method='post'>

		<p><label>Title</label>	<input type='text' name='title' value='<?php if(isset($error)){ echo $_POST['title'];}?>'></p>

		<p><label>Description</label><br />
		<textarea name='description' cols='50' rows='5'><?php if(isset($error)){ echo $_POST['description'];}?></textarea></p>

		<p><label>Date of Event : (y-m-d) :</label><input name="event_date" type="date" value='<?php if(isset($error)){ echo $_POST['event_date'];}?>'></p>

		<p><input type='submit' name='submit' value='Submit'></p>

	</form>