Get the server name using superglobal $_SERVER and add rest of the path.

$path = $_SERVER['SERVER_NAME'].'/the path';
header("location: " . $path ."/dashboard.php");

because you enclose it in double quotes below is correct as well

header("location: $path/dashboard.php");

Instead of: header("Location: ../first.php")

try with this: header("url: ../first.php")

this will change the url.Using location don't work in some cases

Since: '../' is to denote 'parent directory'.So,this will work.

Well, if the server sends a correct redirection header, the browser redirects and therefore "changes the url". It might be a browser issue, then. I don't know if it has anything to do with it, but you should not send a relative url in the location header ("HTTP/1.1 requires an absolute URI as argument to » Location: including the scheme, hostname and absolute path, but some clients accept relative URIs. ", http://php.net/manual/en/function.header.php), and "location" must be capitalized, like:

header('Location: http://myhost.com/mypage.php');

The accepted answer will take you to the root of the domain, not 1 folder up as specified.

To go one folder up:

header("Location: ../landing.html");

You could theoretically create a PHP File at the Root of your Application and call it anything you like: say redirect.php. Then inside of this redirect.php, you could put some code that might look something like this:

<?php
    // CREATE AN ARRAY THAT WITH NUMERIC KEY
    // THAT WILL CORRESPOND TO THE FILE YOU WISH TO REDIRECT TO (ACTUALLY LOAD)
    // SINCE THIS IS A PSEUDO REDIRECT:
    $fileMap            = array(
        0   => "./file-1.php",
        1   => "./file-2.php",
        2   => "./file-3.php",
        3   => "./file-4.php",
        4   => "./file-5.php",
        5   => "./file-6.php",
        6   => "/cert/forms/sessions/session-inc-info.php",
        7   => "./../../session-inc-info.php",  //<== YOU MAY KEEP ADDING TO LIST
    );

    // CHECK THAT THERE IS A GET PARAM WITH NAME: to
    if(isset($_GET['to'])){
        $fileKey        = $_GET['to'];          //<== GET THE `to` PARAM FROM $_GET
        $loadableFile   = $fileMap[$fileKey];   //<== TRANSLATE `to` KEY TO A LOADABLE FILE

        // IF THE FILE [$loadableFile] EXISTS, LOAD IT
        // OTHERWISE REDIRECT TO MAIN-APPLICATION PAGE (HOMEPAGE)
        if(file_exists($loadableFile)){
            require_once $loadableFile;
        }else{
            header("location: index.php");      //<== ASSUMES index.php IS THE MAIN FILE.
            exit;
        }
    }

    // IF ALL FAILS, STILL REDIRECT TO THE MAIN-APPLICATION PAGE
    header("location: index.php");              //<== ASSUMES index.php IS THE MAIN FILE.

Then on each page where you wish to Perform a redirect, you may simply do something like this:

<?php
    // ASSUMING YOU WANT TO RE-DIRECT TO: `./../../session-inc-info.php`
    // AS YOU CAN SEE FROM THE `$fileMap` ARRAY, `./../../session-inc-info.php`
    // HAS THE KEY OF "7"
    // NOW ALL YOU CAN DO IS SIMPY APPEND "?to=7" TO `redirect.php` 
    // IN THE `header()` METHOD LIKE THIS:
    header("location: redirect.php?to=7"); 
    exit;
    /*EXPECTED TO LOAD THE FILE: `./../../session-inc-info.php`

NOTE:
This is not really a Redirect (as it is basically just loading[including] Files from a given Location/Path, however since it seems you are trying to load some file like: /cert/forms/sessions/session-inc-info.php, it is assumed that this may be an option. To do a real Redirect: just use the header() Function directly passing it the exact URL-Location to which to redirect.

Cheers and Good-Luck...