Forgot my root password and now unable to login with ssh

I am newbie to BBB in my first interaction with BBB I login into BBB with putty and changed the root password now I Forgot password.
Now I when i Try to login to BBB using putty following session takes place
login as: root
root@ 's password:

and it keep on asking the password which i cannot remember please HELP

Try to login as the normal user and use sudo to reset the root password,
there's a chance this will work (it depends on the image you're running)
and it's the easiest solution. If you can't connect via ssh, hook a
keyboard and monitor to the BBB, since most images are setup to
automatically log you in when they boot.

Otherwise, if you are not familiar with Linux, just reflash the BBB.

If you are familiar with Linux and uBoot, you can pass init=/bin/bash to
the kernel as a command line argument (using the serial port, or by
editing uEnv.txt if you boot from uSD). This will let you boot into
your system as root and you can reset the root password.

If you are booting from a uSD card, mount it in another Linux system and
edit the /etc/shadow file to reset or remove your password.

If you're booting from eMMC, boot from uSD instead, the latest Debian
image should work well for this:

...again, edit the /etc/shadow file on the eMMC and reset/remove the
root password.