Understanding ChangeSet Action. No pending_1 readlink is created.

[daniyal123]

I am exploring changeset action in sample demo application. I am using sample odata espm as service. I want to store SalesOrderHeaders and SalesOrderItems.

From SalesOrderHeaderList Page, I have ChangeSet action which then calls navigation to SalesOrderHeader Create Page. On create Page, I have save action which uses CreateEntity Action to save SalesOrderHeader and navigates to SalesOrderItemCreate Page. On this page I want to save SalesOrderItem and link it to the SalesOrderHeader, but i am not able to do it. According to my understanding of changeset, the readlink for SalesOrderHeader should be pending_1, but it is something SalesOrderHeader(lodata_sys_id='...').
Can anyone help me to understand this. I am using modal page in navigation.

Also in changeset if modal page cancel action is executed, all changes should be reverted, but it not happening in my case. When I save SalesOrderHeader and in SaledOrderItem page, i click on cancel, the SalesOrderHeader is still saved.