Somethings you need to update a subscribers subscription length or adjust it because they only want access for a certain range or may have suffered a delay on the start of their subscription. You can do this by going to accounts as shown in the screenshot below.
By clicking on this you will get a pop up that will show the subscription history of a subscriber, from here you can cancel their subscription, issue a refund, email them a receipt for their subscription or suspend the subscription via the drop down menu on the right, then hit the submit button to action it.
If you wish to adjust the length of a subscription you can do so by clicking on the start and end date of the subscription as shown below.
This will bring up a page which will have options for adjusting the start and end date of a subscription. For this example, we are going to adjust it to start on the 25th of april 2020. By adjusting the start date, it will automatically adjust the end date based on the length of the subscription type once we hit update.