Change status of orders from "processing" SOLVED

Hello,
I'm using 1.5.6 and all my orders say "processing" when I look under sales>orders. My situation is about 35% of my orders pay me through the mail, so I'm waiting on payment from these orders.
I use ShipStation which interacts with Opencart but it pulls ALL orders into ShipStation ready to be shipped. Once its shipped, ShipStation tells Opencart and it shows shipped in OpenCart.

ShipStation says I can map orders such as "pending" orders.

I'm new to opencart and Im lost of how to change these orders at checkout that are not paying via credit card or bitcoin and I'm waiting on their payment. Can I change them to pending? If a customer selects money order/cash as the payment option at check out, can I some how assign these orders to "pending"?

UPDATE: I figured this out. For my payment options, I use a Variable Payment extension. In that extension I changed my mail order payment option to PENDING. So when a customer uses that payment option, the order is automatically set to PENDING. Ship station works with OpenCart to not import PENDING orders, which you can change and map this in ship station. Now when I receive the money from the customer, I can manually change the PENDING to PROCESSING, then ship station will import it for shipping.