MacOS Sierra: I forgot my password but have the SSD's Filevault recovery key. Can I reset my password?
Please refer to this Support document by Apple:

Reset using your Recovery Key (FileVault must be on)
If FileVault is turned on and you have a FileVault Recovery Key, you can use that key to reset your password.

At the login screen, keep entering a password until you see a message saying that you can reset your password using your Recovery Key. If you don't see the message after three attempts, FileVault isn't on.

Click &gt;  next to the message. The password field changes to a Recovery Key field.

Enter your Recovery Key. Use uppercase characters, and include the hyphens.

Follow the onscreen instructions to create a new password, then click Reset Password when done.

Determine whether to create a new login keychain.


If you can't log in with your new password after restarting your Mac, take these additional steps:

Restart again, then immediately hold down Command-R or one of the other macOS Recovery key combinations until you see the Apple logo or a spinning globe.
When you see the macOS Utilities window, choose Utilities &gt; Terminal from the menu bar.
In the Terminal window, type `resetpassword, then press Return to open the Reset Password assistant pictured above.
Select ”My password doesn't work when logging in,” then click Next and follow the onscreen instructions for your user account.