If the organization already has and utilizes an Enterprise Account, then the simplest way to access that data is to be added to the Enterprise Account as an additional QA. Since the Enterprise Account is designed for that purpose, a licensed IDI Qualified Administrator would have access to any data that is in that account.
If there is not an Enterprise Account in place, then an Enterprise Account would need to be created first. From there, the QA(s) housing that data will need to be added to an Enterprise Account and re-assign the data to the new account. Only at that point would any additional QA have access to the organization's IDI data.
If one of the QAs whose account houses the organization's data is no longer with the organization, then you can contact IDI, LLC to manage re-gaining access to that data (this does require having an Enterprise Account for the organization/department and a licensed IDI Qualified Administrator to access the account).