Update connection string for Imported PBIX file

Dear Techies,

I have to import PBIX files to multiple workspaces. Each workspace is meant to point diffrent Analysis Services DB and we have on premises gateway for this instance The Problem when I try to Import PBIX files using Import API. Connection string is same across all the workspaces. Which should not be the case, PBIX file should point to its respective Analysis Services DB.

Is there a way to update the connection string for all the PBIX files in workspaces?

Please post the sample code 

Thanks in Advance,

Latheesh