Hello Karthik, 

There isn't a way to unlock released ruleset versions. DMSample data initialization actually offers an extensible mechanism that allows you to add a customer by simply changing the source data used to generate the database table entries:

1. Create a new ruleset version or use a branch. If you are planning to upgrade the system to a newer version, make sure the ruleset version will not collide with future Pega Platform releases; for example, add something like a 07-10-99 ruleset version.
2. Look for the DMSampleCustomerData text file and save it in the open ruleset version or branch.
3. Add the line with the values corresponding to the new customer and check in your changes. Note that this will only add a new customer entry. Without subscriptions, devices and purchases, this new customer is not entirely ready to be used in DMSample decisions. You can add the corresponding data to the DMSampleDeviceData, DMSamplePurchaseData and DMSampleSubscriptionData text files.
4. Run the data initialization case.

Hope this helps,

Iolanda