Unable to enable "Allow Updates from REST Service" for existing Source Document Type

Summary:

In RMCS, I want to query and update the column DATA_TRANSFORMATION_STATUS using REST API and with 24C, it asked to enable "Allow Updates from REST Service" for existing Source Document Type so that this data can be queried/update using REST API. However,

when I navigate to 'Manage Source Document Types' task, it is not allowing me to enable this check box to the existed Custom Source Document Type and also not even when I create new custom Source Document Type.

https://docs.oracle.com/en/cloud/saas/readiness/erp/24c/fins24c/24C-financials-wn-f33478.htm#Steps-to-Enable

Can someone help to elaborate more on this topic and also