FAQ Q290: What are corective invoices and how to use them?
Sekcja: Setting up your pricing and invoicing
Parent and corrective invoices.
    You can turn on parent and corrective invoices (multiple invoices) in 
Site settings / Invoice settings.
    On that page you can choose between single and multiple invoices per reservation. If you choose single invoices, changes to a reservation will also update the existing invoice document. For multiple invoices, you can choose when the parent (original) and corrective invoices will be generated for a reservation. With multiple invoices, each newly created invoice has a sequential number that is unique for your Planyo site; the parent invoice simply lists original reservation items and the corrective invoice shows only the items that were added or removed since the previous invoice was generated. Note that with "multiple invoices", an invoice generated once will never be modified.
    
    For multiple invoices, you can choose when the parent (original) and corrective invoices will be generated for a reservation -- each newly created 
    invoice has a sequential number that is unique for your Planyo site; the parent invoice simply lists original reservation items and the corrective invoice shows only 
    the items that were added or removed since the previous invoice was generated.
    
    On the 
Invoice settings page you can choose whether you want to create parent and corrective invoices for your reservations only manually or also automatically. You can choose to create 
    the parent invoice when the reservation is confirmed, when payment is received or when the customer has been checked out. The corrective invoice can be created only when the parent invoice for 
    the reservation already exists and when any reservation item has been modified since previous invoice.
    You can have corrective invoices added automatically when a payment is received or when the customer has been checked out.
    
    You can view the list of invoices generated for your Planyo site on the 
Invoices page. You can also customize the layout of both parent and corrective invoices in 
    
Parent invoice template and 
Corrective invoice template.