add_filter( 'frm_time_to_check_duplicates', '__return_false' );

add_filter('frm_time_to_check_duplicates', 'change_duplicate_time_limit_one_form', 10, 2);
function change_duplicate_time_limit_one_form( $time_limit, $entry_values ){
	if ( $entry_values['form_id'] == 100 ) { //change 100 to your form ID
		$time_limit = 0;
	}
	return $time_limit;
}

add_filter('frm_time_to_check_duplicates', 'change_duplicate_time_limit_one_form', 10, 2);
function change_duplicate_time_limit_one_form( $time_limit, $entry_values ) {
    if ( $entry_values['form_id'] == 100 ) { //change 100 to your form ID
        $time_limit = 31536000;
    }
    return $time_limit;
}

You may also want to use frm_duplicate_check_val to remove an IP address or other value from the check that may be unique to the duplicate entry.

add_filter('frm_time_to_check_duplicates', 'change_duplicate_time_limit_every_form');
function change_duplicate_time_limit_every_form() {
   return 31536000;
}