Hello, thank you for reaching out to Microsoft Q&A.
Unfortunately, you cannot unlock the drive without the BitLocker Recovery key. If the data on the computer is important, you will need to find the key in your Microsoft account. If the account associated with the key is locked, you will have to try the account recovery options, such as using the Account recovery form.
Remember to use a familiar device that you've frequently used to access your Microsoft account, as well as a known location. Microsoft will review your responses and respond within 24 hours. If you're verified, instructions on how to log back into your account will be sent to you; if you're not verified, you'll need to submit the Account Recovery form again. You can do this up to two times every 24 hours.
If you're unable to regain access to your account, you will have to reinstall Windows on your PC, which will completely wipe all data on your HDD. There are no other options to bypass the BitLocker encryption.