Unable to change sales_order status form "not_invoiced" to "invoiced"

Unable to change sales_order status form "not_invoiced" to "invoiced"

I am automating process of creating of invoice from sales_orders by consolidated sales_orders of each customer and creating a single invoice per customer every month. I am doing this in workflow schedule custom function where i create invoice by getting list_items of each order and creating a invoice from them. Simultaneously changing status of sales_order to "invoiced" via "zoho.book.updateRecord" but even after successful response from this api the status doesn't change. 
So is there any way to change it's status i also tried to asscocate this sales_orders with invoice (many sales_order to single invoice) and i was not able to find any endpoint for that. /maptoorder is one possible endpoint but i don't know if it works i couldn't any documentation for that.