In VNX We have CIFS share in standalone CIFS server, we forgot the administrator password to access the share, how to reset or recover the administrator password.

for security reasons there shouldnt be an easy procedure to do this

you can open a service request and check whether customer service can do this via login/webex and internal commands

Other option is to delete the CIFS server and recreate it with the same name

that should keep the shares - if not you have to recreate them

To echo Rainer on this one, yes, just delete/recreate the Standalone CIFS server.  It's soooo much faster and easier.  You can do it faster than you can open a ticket, without affecting data.  The VNX guide has the procedure to create the CIFS server - just follow the steps and off you go!