I want the appointment confirmation to show beginning and end times.

I want to modify this line in appointments.php:

$start = '<label><span>'.__('Begins: ', 'appointments' ). '</span>'. apply_filters( 'app_confirmation_start', date_i18n( $this->datetime_format, $start ), $start ) . '</label>';

So that the end result shows:

Date and time: January 13, 2014 6:00 pm – 7:00 pm

instead of:

Date and time: January 13, 2014 6:00 pm

Is this possible? Thanks!