converting a multi-decisional array

Hello,

I am in need to convert this older version of  PHP array code to a newer format because I am getting an error "Uncaught Error: Cannot use string offset as an array in, etc…” :

$avs[$row['sda_day_number']][] = 
	array(
			'dn'		=>	$row['sda_day_number'],
			'start'		=>	date('g:i a', strtotime($row['sda_start'])),
			'end'		=>	date('g:i a', strtotime($row['sda_end'])),
			'pstart'		=>	$pstart,
			'pend'		=>	$pend,
			'order_id' => $row['order_id']
		);



For the life of me I cannot find the proper combo of syntax for the newer version to not choke on it and the page to display properly.

Appreciate any help.

Don