Hi Naveen,
For which partner do you want the details in the assignment block? Could you elaborate on your requirement?
Create a context node with BOL entity BuilHeader.
The basic idea to meet the requirement is firstly you need to fetch the PARTNER_GUID.
Then use dynamic query BuilHeaderAdvancedSearch and pass the PARTNER_GUID and fetch the result and set the context node with the result.
Let me know if you need any further inputs.
Regards,
Sayan