<a href="deleteresnext.php?rid=< ?php echo $row->rid ?>"
onclick="return confirm('Are you sure you want to cancel reservation?');" >
Delete
</a>
Can I retrieve 2 values using this code ? Because I need it to another php file, I would like to retrieve rid and roomid by the code above ?
Yes. You can add another parameter to that URL:
<a href="deleteresnext.php?rid=<?php echo $row->rid; ?>&roomid=<?php echo $row->roomid; ?>" onclick="return confirm('Are you sure you want to cancel reservation?');" >Delete</a>