As long as the file is from 2016 or earlier version you could open it in Enterprise 2016 (and convert in the process) but if it is new enough to have a password you are up a creek without a paddle. You would need at a minimum the email and account info from the original admin (or enough bluster to get a support rep to help you set up a new access)
Start QuickBooks Desktop Enterprise, then open the company data file you used with your previous version of QuickBooks.
If prompted, enter the Administrator password.
When prompted, select the"I understand that my company file will be updated to this new version of QuickBooks"checkbox, then clickUpdate Now.
ClickOKwhen prompted to back up your data.
In theCreate Backupwindow, follow the onscreen prompts to back up your company file.
When prompted to confirm that you want to update your file, clickYes