To change those passwords you will need to contact your sales team to open an RPQ. Once that has been done support can assist with changing them as they require root level access to change. -ChrisP
How do you change the default passwords for xmsadmin and xinstall?  I have read the doc. [URL]  And this support article.  [URL]  The support article doesn't address how to change passwords for xmsadmin and xinstall.
Change default passwords for xmsadmin and xinstall