Hello! @User17732575520824969410
Welcome to the LastPass Community.
We are sorry to hear that you are having problems changing the master password for one of your family members, you can request the family member to follow the steps in this guide to reset it on their end: Reset your master password using a one-time password
Or if trying to change the master password through account settings, please use the Customer Support contact form here to request additional assistance.
Once they regain access, it's also a good idea to set all available recovery options for their login, and ensure they are logging in with the account password regularly, which keeps a local cache of recovery passwords available to use.
