To change your next order date, please visit the Manage Subscriptions link on the My Accountpage. Navigate to the product(s) you wish to change and click/tap the dropdown for Frequency to the right of the product name.
Please select a new frequency for your order and confirm your selection. From now on, your next order will be shipped based on the subscription frequency you've chosen. You should see a green dialogue box appear on screen, confirming your indicated change.
For example, your order date was August 12th, and you updated it to August 29th. If your subscription frequency is set to one month, your next order will now be shipped on September 29th. If your frequency is set to two weeks, your next order will be shipped on September 12th.