This article also answers:

Is it possible to change the trial end date using the APIs?

You can either extend or shorten the trial period for a subscription using the 'Change Trial End' option in the web interface. Here’s how to do it:

1. Open the subscription for which you would want to change the trial period.

 2. From the right panel, select the 'Change Trial End' option as shown:

3. Enter the New Trial End Date.


4. You’ve now successfully changed the trial end date of a subscription!


You can use  Change Term End API if you're an API user.