Read the related manuals.
Passwords of external accounts are managed external contact those admins. You should know the admins of: AD, LDAP, RACF and the RDBMS systems.
They are registrated in SAS-metadata and possible config-files changing passwords is requiring to change them at all locations. the SDW should give help with that.
Internal accounts are used in a similar way in that case there is a similar approach. The only difference is admin is the SAS-admin.
The unrestricted SAS-admin (sasadm@saspw) is the bootstrap of security. IF you do not have that password there is problem to solve
When you can get to the adminusers.txt file you can define an other account also as the unrestricted SASadmin. Restart everything and than change the original key internally.
The bad thing with this is that this key is also used internally by eg Eminer. so check those definitions first to be sure you can fix everything to a running state.
If you are Lucky... the config files of the installation could be still there they can contain lcoations and passwords (encoded).
---->-- ja karman --<-----