You need to create a test platform first, execute all the steps and check that all the services works fine, here are the steps:

CurrentDocbaseName= Your Actual Docbase Name
NewDocbaseName = The New Docbase name

1. Using DQL or API obtain and write down the r_object_id of your docbase config object, you will need this in 12.a
2. Using DQL or API obtain and write down the r_object_id of your server config object, you will need this in 12.b
3. Obtain and write down the documentum server name, you need this in 12.c
4. Shutdown all the documentum services
a. Docbase
b. Docbroker
c. Method server
5. Rename the following at file system level
a. \Documentum\apptoken\OldDocbaseName.tkn to
 \Documentum\apptoken\NewDocbaseName.tkn
b. \Documentum\cache\X.X\bof\CurrentDocbaseName to \opt\Documentum\cache\X.X\bof\NewDocbaseName
c. \opt\Documentum\data\CurrentDocbaseName to \opt\Documentum\data\NewDocbaseName
d. \opt\Documentum\dba\auth\CurrentDocbaseName to \opt\Documentum\dba\auth\NewDocbaseName
e. \opt\Documentum\dba\config\CurrentDocbaseName to \opt\Documentum\dba\config\NewDocbaseName
f. \opt\Documentum\dba\log\OldDocbaseName.log to \opt\Documentum\dba\log\NewDocbaseName.log
g. \opt\Documentum\dba\log\fulltext\fttrace_CurrentDocbaseName.log to \opt\Documentum\dba\log\fulltext\fttrace_NewDocbaseName.log
h. \opt\Documentum\server_uninstall\delete_db\CurrentDocbaseName to \opt\Documentum\server_uninstall\delete_db\NewDocbaseName
i. \opt\Documentum\share\temp\ldif\CurrentDocbaseName to \opt\Documentum\share\temp\ldif\NewDocbaseName
j. \opt\Documentum\share\temp\replicate\CurrentDocbaseName to \opt\Documentum\share\temp\replicate\NewDocbaseName
6. Edit \opt\Documentum\dba\config\NewDocbaseName\ server.ini file, change the following keys
a. docbase_name=CurrentDocbaseNameto docbase_name=NewDocbaseName
b. server_config_name=CurrentDocbaseName to server_config_name=NewDocbaseName
c. service=dm_CurrentDocbaseName to service=dm_NewDocbaseName
7. Save changes and close the server.ini file
8. Edit \opt\Documentum\dba\documentum.ini file, change the following keys
a. [DOCBASE_CurrentDocbaseName] to [DOCBASE_NewDocbaseName]
b. NAME=CurrentDocbaseNameto NAME=NewDocbaseName
9. Edit C:\WINDOWS\system32\drivers\etc\services file, change the following keys
a. dm_CurrentDocbaseNameto dm_NewDocbaseName
b. dm_CurrentDocbaseName_s to dm_NewDocbaseName_s
10. Edit \opt\Documentum\config\dfc.properties file, change the following keys
a. dfc.bof.registry.repository=CurrentDocbaseName to dfc.bof.registry.repository=NewDocbaseName

**This step is required only if this repository was configured as the Global Registry

10.a
Change the service name in \etc\services\
11.
i. Change the path \opt\Documentum\dba\config\OldDocbaseName\server.ini to \opt\Documentum\dba\config\NewDocbaseName\server.ini
ii. Change the log file name \opt\Documentum\dba\log\OldDocbaseName.log to \opt\Documentum\dba\log\NewDocbaseName.log
12. In the database execute the following sql commands
a. UPDATE dm_sysobject_s set object_name = 'NewDocbaseName' where r_object_id = 'DOCBASE_CONFIG_OBJECT_ID';
b. UPDATE dm_sysobject_s set object_name = 'NewDocbaseName' where r_object_id = 'SERVER_CONFIG_OBJECT_ID';
c. UPDATE dm_job_s set target_server = 'NewDocbaseName.NewDocbaseName@HOSTNAME';
d. Also remember to change the old root in the file_system_path attribute of the dm_location_s table
13. Restart the content server


WARNING- I have no responsiblity if it doesnt work, it depends on system to system how is your system configured. Please do it at your own risk.

I would again recommend to do it on dev env.

Good Luck