need php script mod help for email checker

I have a php script that I need to modify quickly but don't know how. This script processes a form on a Wordpress site and sends a copy to two email addresses. It is currently set to query a mysql db to see if the registrant is already registered. If they are, the script will not send an email to the two $mail_to = addresses. I need to change that so it will regardless of duplicate registrations. The script now is

      $sql_email_check = "select * from tbl_search_details where str_email ='$email'";
            $rs_email_check = mysql_query($sql_email_check);
                         
             if(mysql_num_rows($rs_email_check)>1){
                  header("Location: http://domain.com/folder");
             }else{      
                        $sql_insert= "insert into tbl_search_details ( str_first_name , str_last_name, str_email , str_phone , str_movein_date , bit_active ) values ('$first_name', '$last_name', '$email', '$phone', '$move_in_date','1')";
                      $rs_insert = mysql_query($sql_insert) or die(mysql_error());
                      $today = date("Y-m-d");
                        list($job_year,$job_month,$job_day)=split("-", $today);
                        $month = date(M,mktime(0,0,0,$job_month,$job_day,$job_year));
                    $ip = $_SERVER['REMOTE_ADDR'];
                        $mail_to = "emailaddress1@gmail.com,emailaddress2@somewhere.com";
                        $mail_subject= "User Registration from Web Site ";