What do you mean by change the config from CTS 55 to TX9000 (What is CTS 55?) Is the device registered as the wrong type? If it helps at all... TX codecs only know what endpoint they belong to per the configuration downloaded from CUCM. A TX codec will assume it's a CTS-500-32 until it gets the config from CUCM and sets itself to be a TX9000 codec (then it will establish the network with ts2, ts3, ts4, etc.).
So what's the actual issue you're having? If for some reason you need to force the codec to be something else you can try "set ctstype" from the admin CLI: http://www.cisco.com/c/en/us/td/docs/telepresence/tx_sw/6_0/command_ref/tx_sw_cli_book/tx_sw_cli_cmd_set.html#35168, this usually isn't required though.
