Key assignment error in SAP MDG

Hi,

1> created a custom data model with Type 1 Entity having key assignments (Key Cannot be changed; No Internal key assignment)

2> Save and activated the data model.

3> But later when I go and change Type 1 entity (key assignment Key can be changed; no internal key assignment) Its giving error not allowing to chnage and activate the data model.

Data model XX is already active and entity type XXXXXX is contained in the active version. In this case, you may no longer change the type of key assignment for entity type XXXXXX.

Please let me know how to get rid of this.

Regards, Riyaj.