It may be possible to reset the root password by booting into single user 
mode, something like this:
https://wiki.centos.org/TipsAndTricks/ResetRootPassword

-- Eremey

-----Original Message-----
From: [log in to unmask] 
<[log in to unmask]> On Behalf Of Elio Fabri
Sent: Tuesday, June 23, 2020 3:50
To: [log in to unmask] <[log in to unmask]>
Subject: Recovering root password

Hi all,
I need help (at lest a link) as to how to recover my root password.
I'm using SL6.2. The password I remember by heart is no longer accepted, 
neither for the su command nor for sudo.
Thx
--
Elio Fabri