Manual Reservations

Dear All,

When i am trying to create Manual reservations the system gives the following error:

You entered an order whose category only permits automatic reservations. The following order categories do not allow manual reservations:

10 PP production order

20 network

30 maintenance order

40 batch order (process manufacturing)

50 inspection lot

Kindly tell me how should i make Manual reservations for the following Order Types

cheers