If you visit your payment section of your store settings, you can add it there. The page will state if you need to receive more orders first before it is available
For an already placed order copy the email provided by Brick Owl contact customer form and send an invoice directly from PayPal, once you received the payment mark the order paid.
@Lawrence sorry if my question wasn't clear enough. IBAN is already enabled in my store, the question was if I can change it for existing orders.
@Stellar I've already contacted the customer and sent him my paypal.me link but no answer or payment yet. It seems that's all I can do or cancel the order.
If you use the same email address for your BO and PayPal accounts, you can tell them to make a payment to the email address they see when they select 'Contact Store' - it will look something like {randomstringofcharacters}@m.brickowl.com.
Otherwise, as @Stellar says, you can send them an invoice from within PayPal to their @m.brickowl.com address.
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@Stellar I've already contacted the customer and sent him my paypal.me link but no answer or payment yet. It seems that's all I can do or cancel the order.
Otherwise, as @Stellar says, you can send them an invoice from within PayPal to their @m.brickowl.com address.