The document provides steps to reset a lost root password in RHEL7 or CentOS7. It involves booting into the GRUB menu and adding "rd.break" to the kernel arguments. This pauses the boot process after mounting the filesystem read-only. The filesystem can then be remounted read-write to change the root password using "echo newpassword | passwd --stdin root" and reset the root account expiration. Creating a file named ".autorelabel" ensures the filesystem is relabelled on reboot to enforce SELinux in the enforcing mode.