When CallManager moves to Linux based (CUCM 5.0 and above), it removes the concept of DC directory. Thus UCCX has to store its configuration on UCCX server in XML files.
Cisco provides a tool called CET (Configuration Editing Tool?) to edit those configurations. The tool is supposed to be used by Cisco TAC only.
For Windows-based UCCX (7.x and before), you may find the CET tool on UCCX server C:\program files\wfavvid\cet.bat. Just the the cet.bat file.
For Linux-based UCCX (8.0 and above), you may find the CET installer on the UCCX installation DVD (\Installer\CetTool\CetTool.exe). Or download from an already-installed UCCX server http://18.104.22.168/uccxinstalls/CetTool.exe (case-sensitive). You'll have to install it on a Windows workstation.
You may use CET tool to modify the configuration of UCCX, such as removing license file or reset the system back to before-initialization state (for password recovery purpose). Please note that on Linux-based UCCX, you'll need a root credential to use CET tool. Either get it from Cisco TAC or follow instructions here.
You may also modify the configuration without CET tool. But it requires some reserve engineering.
For example, you want to set the UCCX 8.5 back to FRESH INSTALL state. You may edit the XML file in /opt/cisco/uccx/ClusterData/default/com.cisco.crs.cluster.config.AppAdminSetupConfig. Look at the blobValue. It's encoded in ASCII.
Translate that with the ASCII table:
46 = F
52 = R
45 = E
53 = S
48 = H
5F = _
49 = I
4E = N
53 = S
54 = T
41 = A
4C = L
4C = L
If you want to set the value to a specific string, you'll translate the string into ASCII code and put it in blobValue.