Guys, Not sure this right forum to post, but expecting some light from you 

I want to avoid bad data coming again and again from source after  validating and updating member in a entity in MDS.

Let me explain.

For particular member  city coming as 'XYZ' from source which is wrong.

So we updated value from explorer with correct value "Boston".

Since data load from source is happening through ETL, next load bring again wrong value into my member city attribute.

Since I cannot update my source data, I need to implement a work around in ETL/T-SQL to identify previous updated value for attribute for members and update value with MDS current value only. 

Can I use DQS for this purpose. If Yes please guide me. 

Any help, will appreciated.

Yes you can Once you correct the value inside DQS domain, the next time data comes through SSIS you can cleanse it against the domain you created it DQS to get the corrected result using DQS task (assuming SSIS 2012) and it will convert all those XYZ values to Boston before saving to database