For the database part of your question just use the native database tools to handle this.  I would probably suggest stopping the server and agent before any of these items. 

For example using MySQL since that is what your configuration shows to change the password for the netnxms user on a MySQL system:

$ mysql -u root -p    # Enter root password when promted
   mysql> use mysql;
   mysql> update user set password=PASSWORD("NEW-PASSWORD-HERE") where User='netxms';
   mysql> exit
$ vi /etc/netxmsd.conf
   # Updated DbPassword with NEW-PASSWORD-HERE in configuration

Similarly, if you wanted to start over with a clean database you would run the following:
BE WARNED THIS WILL WIPE YOUR DB SETUP COMPLETELY TO INITIAL VALUES!!!

$ mysql -u root -p    # Enter root password when promted
   mysql> drop database netxms;
   mysql> exit
$ /usr/local/bin/nxdbmgr init  /usr/share/netxms/sql/dbinit_mysql.sql     # Path might be /usr/local/share... based on install

tnx, sorry but i'm write this reply for another theme, my mistake, sorry again > https://www.netxms.org/forum/general-support/nxdbmbr-bug/
i knew it, but i mean remove configuration only.
i think using another or bultin tools is a wrong way.

For example using MySQL since that is what your configuration shows to change the password for the netnxms user on a MySQL system:

$ mysql -u root -p    # Enter root password when promted
   mysql> use mysql;
   mysql> update user set password=PASSWORD("NEW-PASSWORD-HERE") where User='netxms';
   mysql> exit
$ vi /etc/netxmsd.conf
   # Updated DbPassword with NEW-PASSWORD-HERE in configuration

Similarly, if you wanted to start over with a clean database you would run the following:
BE WARNED THIS WILL WIPE YOUR DB SETUP COMPLETELY TO INITIAL VALUES!!!

$ mysql -u root -p    # Enter root password when promted
   mysql> drop database netxms;
   mysql> exit
$ /usr/local/bin/nxdbmgr init  /usr/share/netxms/sql/dbinit_mysql.sql     # Path might be /usr/local/share... based on install

To change user information, you can go to COnfiguration -> User Manager in console. There you can change password and user details. You can also change password for the user you are currently logged in with via Tools -> Change password menu.

Best regards,
Victor

it work, tnx. How about nxmbrmgr? And i think need some new options for nxdbmgr, -delete configuration from database or overwrite.

Best regards,
Victor

Here is my /etc/netxmsd.conf file:
#
# Sample configuration file for NetXMS server
#

#
 DBDriver = /usr/local/lib/libnxddr_mysql.so
#
# Database driver to use
#
# UNIX example:
# DBDriver = [path_to_netxms_install_dir]/lib/libnxddr_mysql.so
#
# Windows example:
# DBDriver = mysql.ddr

#
 DBServer = localhost
#
# Database server (ODBC source name for ODBC driver)
#
# Example:
# DBServer = localhost

#
 DBName = netxms
#
# Database name (not used by ODBC driver)
#
# Example:
# DBName = netxms_db

#
# DBLogin
#
# Database user name
#
# Example:
# DBLogin = netxms

#
# DBPassword
#
# Database user's password
#
# Example:
# DBPassword = password

#
# LogFailedSQLQueries
#
# Controls logging of failed SQL queries.
# Possible values: "yes" (default) or "no".
#
# Example:
# LogFailedSQLQueries = yes
DBlogin = root
DBPassword = mypass
LogFile = /var/log/netxmsd
LogFailedSQLQueries = yes

#
# LogFile
#
# Server's log file. To write log to syslog (or Event Log on Windows),
# use {syslog} as file name.
#
# Examples:
# LogFile = {syslog}
# LogFile = /var/log/netxms

Thank you for help

Do you have libnxcore.so.1 in /usr/local/lib? If yes, try to run ldconfig and then start netxmsd again.

Best regards,
Victor