Sometimes a config error, lost root password, broken fstab entry, or failed filesystem leaves a RHEL system stuck. The recovery toolbox covers three common scenarios: (1) lost root password → either rd.break or init=/bin/bash at the GRUB menu; (2) broken fstab mount → boot into emergency.target and edit /etc/fstab; (3) broken service preventing boot → boot into rescue.target and disable the offender. All three rely on editing the kernel command line at the GRUB menu to change the early-boot behavior for one boot.
For password reset, know both rd.break (the classic recipe, still on every RHCSA reference sheet) and init=/bin/bash (the modern alternative that's more reliable on RHEL 10 and skips the /sysroot chroot dance). Either will work on the exam; pick the one whose mental model sticks.