If the date of birth is edited by a few days or months, after you have started using Goal, the default retirement, mortality events and State Pension start date will need to be edited to match the new date, this will not be done automatically by the tool.
If the date of birth is edited by more than 12 months, its worth adding a test client with the date of birth and then clicking the 'Current plan' tab to view the estimated Mortality date. Once done, go back to the client and update the mortality date to this one.