title: Allow end user to modify recurring paypal subscription amount
body: <p>I've read a few responses here regarding the modification of the recurring fee amount but still confused. </p>
  
  <p>We have 5 subscriptions levels per month:
  £10 
  £15 
  £20
  £30 
  £50</p>
  
  <p>We want to be able to let customers change their subscription package to any of the other options. </p>
  
  <p>It sounds like if they are changing to a package with more than 20% difference from the one they are on - we would have to make them cancel and start a new subscription.</p>
  
  <p>Surely there is a way to have the subscriber confirm they are happy to change the amount?</p>
  
  <p>thanks</p>