Auto Provisioning rules to change from seeded to custom role for existing user population

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We have set auto-provisioning rule set for seeded Employee role to be assigned to all the employees. We wanted to replace with the custom employee role due to a change in requirement. 

What is the best practice to replace the seeded employee role with custom employee role for all the current employees without any impact? Can we request the oracle support to update from the backend and then modify the existing auto-provisioning rule?

Any pointers highly appreciated!

Thanks, Vijay