You might also find your answer in the LastPass Enterprise Manual.
How do I set up SuperAdmin Password Reset policy and reset master password for a user?
How do I set up Master Password Reset Policy?
1. Go to LastPass Admin Console
2. Click on Setup > Add Policy > select the policy
3. Click Show List link > enter your email address (or any other users' if you want to make them super admins).
4. Click Save to save the email address on the list
5. Click Save to enable the policy
6. Have everyone re-login using LastPass extension on their browsers once so their encryption keys can be securely shared with super admins
If it is set up and everyone re-logs in as advised, you will see Super Admin Master Password Reset option on the drop-down list by going to Admin Console > Users > clicking on the down arrow under Action column.
I am the Super Admin but I don't see this option for a user. Why?
This policy must be enabled before the administrator needs to reset the user's password. Once the policy is turned on, new accounts will be able to have their passwords reset. Existing users will need to log out and and back in to their accounts using LastPass plugin on the browsers at least once before the administrator will have the option to reset their password. It would not work if they re-login via lastpass.com.
If the user is currently locked out and cannot be reset, have them undergo account recovery steps here instead.