unable to find what is the error of PHP update

I am working on a web page where a doctor can update patients information, including adding PDF files to his ID row in SQL. When I try to insert new patient data, the file is added to the directory and can be downloaded, but when I click on the update page of a row of a patient, even if I didn't upload a new file because I don't need to change the last file, and then I click on update button and the file path is changed into some unknown format. And when I want to update a patient and add a new file to it, I can't either.
The code is:

<?php 
require_once ('../include/global.php');
$id=$_REQUEST['id']; 

  if (isset ($_POST['name'])) { 
$name = $_POST['name']; 
} 
if (isset ($_POST['remarcs'])) { 
$remarcs = $_POST['remarcs']; 
} 
if (isset ($_POST['test_res'])) { 
$test_res = $_POST['test_res']; 
} 
if (isset ($_POST['address'])) { 
$address = $_POST['address']; 
} 

if (isset ($_POST['date'])) { 
$date = $_POST['date']; 
} 

if (isset ($_POST['phone_num'])) { 
$phone = $_POST['phone_num']; 
}

if (isset ($_POST['illness'])) { 
$illness = $_POST['illness']; 
} 
if (isset ($_POST['echo'])) { 
$echo = $_POST['echo']; 
} 
if (isset ($_POST['pe'])) { 
$pe = $_POST['pe']; 
} 
if (isset ($_POST['pmhx'])) { 
$pmhx = $_POST['pmhx']; 
} 
if (isset ($_POST['pshx'])) { 
$pshx = $_POST['pshx']; 
} 
if (isset ($_POST['habbits'])) { 
$habbits = $_POST['habbits']; 
} 
if (isset ($_POST['occup'])) { 
$occup = $_POST['occup']; 
} 
if (isset ($_POST['allergy'])) { 
$allergy = $_POST['allergy']; 
} 

//Check file is uploaded or not 

$path = "../uploads/".$_FILES['file']['name'];
//$path2 = "../uploads/".$_FILES['echo_photo']['name']; 

//move_uploaded_file($_FILES["file"]["tmp_name"], $path);
$new_path = $path; 
$sql="UPDATE $tbl_name SET  
name = '$name', 
echo_files = '$new_path', 
remarcs = '$remarcs',
test_res = '$test_res', 
date = '$date', 
address = '$address', 
phone_num = '$phone',
illness = '$illness',
echo = '$echo', 
pmhx = '$pmhx', 
pshx = '$pshx', 
habbits = '$habbits', 
occup = '$occup', 
allergy = '$allergy',
pe = '$pe'
WHERE id = ".$id; 

$result=mysqli_query($con,$sql) or die('Unable to execute query. '. mysqli_error($con));
if($result){
    header("location:../SearchOrView.php");

}
 else { 
//header("location:update_false.php");
die('Unable to execute query. '. mysqli_error($con));


}
?>