Yes, through your sidecart.
Your sidecart allows you to potentially save money on shipping by having new orders shipped with future subscription shipments. If you have an active subscription, each time you go through checkout, you'll be be given the option to combine new items with the earliest possible subscription shipment. If you choose to combine them, they'll be placed into your sidecart until that subscription shipment is ready. (This option doesn't apply to backorders, preorders from publishers other than Paizo, and items that do not require shipping.)
You can view the items in your sidecart by going to your My Account page and viewing the Sidecart box on the lower right side—you may have to scroll down a bit to see it.
If you decide you don't want to wait until the next subscription shipment to receive your sidecart items, just click the "ship as soon as possible" button in the Sidecart box. This will take you to an order confirmation page to review the items, payment method, and shipping details before completing the order process.
If any of the items is your sidecart are out of stock when your subscription is ready to ship, your subscription shipment will not be delayed; we'll ship any in-stock items along with the subscription, and any out-of-stock items will remain in your sidecart to ship with a future subscription shipment.