Renaming the Data Sets in SSRS
The correct answer would be to say yes - however, a quick win is to close your solution, then open the .rdl file up with notepad and do a find-and-replace. Then save your .rdl file and re-open your solution - you should find all of your references within the report have been updated. Remember that the .rdl file is essentially an xml file, open it up and have a look around - it will help you understand the inner workings better. You will of course need to update the data source yourself though.

I hope this helps you.