title: How to show date in php. using getFormatDateTime and strtotime
body: <p>Before I start I should mention that I have no knowledge about coding, so please bear with me if my question doesn't make sense.
  I bought a plugin for taxi reservation for wordpress. Everything works fine except that when the user picks the date after checking out in woocommerce the reservation date and time is changed to: <code>01-01-1970 12:00 AM</code> and therefore all dates are wrong in emailed receipts as well as the woocommerce orders section.</p>
  
  <p>Since the author is not providing any support on this, I had to dig into it myself and I noticed it's using the following to show the date after checkout:</p>
  
  <p><code>$dateTimePickUp = date(getFormatDateTime("php"),strtotime(WC()-&gt;session-&gt;get_post_meta( $order_id , 'dateTimePickUp', true )));</code></p>
  
  <p>Since this was not working I used the code the was used before checkout:</p>
  
  <p><code>$dateTimePickUp = date(getFormatDateTime("php"),strtotime(WC()-&gt;session-&gt;get( 'dateTimePickUp' )));</code></p>
  
  <p>Now everything is fine except that in the woocommerce orders section I'm getting a Fatal error.</p>
  
  <blockquote>
    <p>Fatal error: Call to a member function get() on null in
    /data/49/4/64/130/4716619/user/5589202/htdocs/OCRides/wp-con‌​tent/plugins/stern_t‌​axi_fare/templates/c‌​heckout/checkoutAfte‌​r.php
    on line 21</p>
  </blockquote>
  
  <p>Now my questions are:</p>
  
  <ol>
  <li>What's the difference between the above codes?</li>
  <li>How can I make the first code work?</li>
  </ol>
  
  <p>Thanks in advance</p>