Once DQS project is executed once it then always opens either at stage 3 (Manage and View results) or stage 4 (Export). So far we were not able to go back to Stage 1 (Map). So how can we modify existing DQS project? What if we want to add one more column to the process or apply a different domain to a column?

Hello,

Once you finish a DQS project by clicking Finish in the Export stage, you cannot change/modify the DQS project in terms of changing the mapping or selecting another KB to cleanse. You can only open the DQS project to review the results in the Manage and view results stage and then Export the resultant data.

If you want to be able to change a DQS project later or to start over again, you must not click Finish in the Export stage. Instead after exporting the results, click Close to just close the DQS project.

Thanks
Vivek
(SQL Server Documentation | Twitter: @vivek_msf