You can process an order earlier than your set shipment date as long as 30 days have elapsed from your last shipment. Log into your account, and under "Upcoming orders" click "Edit" and choose to ship now from the dropdown box.
You will be charged immediately and, if the payment is successful, the pharmacy will fulfill and ship your order within 1-3 business days. Your next shipment date will update to 90 days from this early shipment date. However, you can always change this date in your account dashboard.