Generally, PGEstore.com has specific policies regarding order modifications once an order has been placed. Typically, customers are unable to add items to an existing order directly. Once an order is submitted, it enters the processing stage, which often prevents any changes. However, customers do have the option to place a new order for additional items if they wish. It is advisable to check the website for any specific guidelines or updates regarding order changes, as this information may vary. Additionally, customers can often find details on how to manage their orders in the help or FAQ sections of the website. If further assistance is needed, looking for contact information on PGEstore.com could provide additional clarity.