Actually Regression Testing done by selecting the test cases which is already prepared. no need to prepare any new testcases for regression testing.
Selection test cases for regression testing is depends on the which regression type testing selected, and previous Test Execution reports (Functional, GUI, Performance, etc [ simply all test cases]).........
Types of regressions as below,
No further test cases are required as we need to run the same set of test cases if any changes have occured as regression testing is done to notify that on certain change or fix other integration or linked items are not affected
This calls for the definition of regression and differentiation between Regression and Retesting.
X Test Cases executed. A path or fix has been provided . you run the same X test cases to ensure that nothing is broken.
In all There are say 3 Modules A+B+C all having test cases X+Y+Z.
Execute only X Test Cases to ensure A Module is working fine. Execute All Y Test Cases to ensure B module is working fine.
This is a example of Local a.k.a Module regression.
Execute all the X+Y+Z test case to ensure nothing is broken in the interfacing of A/B/C is called Global regression.