Can we split non shippable line?

Summary:

We have a requirement of Bill only line will be created in the sales order with header total of 1000$, this will be communicated to the customer, whenever partial service completed we have to pay partially not in full header total.

And for the bill only line, as soon as we submit the order, order line status goes to Awaiting billing, post that , we cannot edit the price or quantity, as a workaround to communicate the customer we asked the business to create sales order with bill only line and put the line ;on hold', so status wont get change to awaiting billing, once the partial service completed now we wanted to split the line, since there is no scheduling involved for bill only line, system not allowing to split the line, is there any way we can split bill