Resetting the SYSTEM User's Password in the admin guide for SP7 discusses how to do this: http://help.sap.com/hhxe/SAP_HHXE_Administration_Guide_en.pdf

Step 1. Login to SAP HANA Server

Log on to the server on which the of the master index server is running

 

Step 2.Switch to SAPHANA Admin user

Now we need to switch to SAPHANA admin user using following command

# su - hxeadm

 

Step 3.Stop the Database

Shut down the instance by executing the following command:

# /usr/sap/HXE/HDB90/exe/sapcontrol -nr 90 -function StopSystem HDB

 

Step 4.Start the Nameserver in Background

Now start the name server in background by executing the following commands (don't forget & at the end of the command line)

# /usr/sap/HXE/HDB90/exe/hdbnameserver &

 

Step 5.Start the  Compile Server in Background

start the compile server by executing the following(don't forget & at the end of the command line)

# /usr/sap/HXE/HDB90/exe/hdbcompileserver &

 

Step 6.Start the Indexserver with Special Flag resetUserSystem

Now start the index server by executing this command

# /usr/sap/HXE/HDB90/hdbenv.sh

# /usr/sap/HXE/HDB90/exe/hdbindexserver -resetUserSystem

Starting interactive mode for resetting user SYSTEM...

If you get error: 

Unable to obtain Service Database Name via environment variable $DBNAME!if started by hand use: DBNAME=XXX hdbindexserver Do NOT use daemon.ini sections [indexserver] or [indexserver.c] to configure the service in mdc; instead use ALTER DATABASE ... ADD 'indexserver'.

hxehost:hxeadm> DBNAME=HDB; export DBNAME

And redo the command line! (# /usr/sap/HXE/HDB90/exe/hdbindexserver -resetUserSystem)

 

Starting interactive mode for resetting user SYSTEM...

service startup...

accepting requests at 127.0.0.1:39003

assigning to volume 2 ...

run as transaction master

resetting of user SYSTEM - new password:

PASSWORD

new pw accepted.

(Re)Activating user SYSTEM...

done

prepare for shutting service down...

Preparing to shutdown...

 

And that's it!