how to change data format from 8-bit to 7-bit with X-CTU?

I want to interface my xbee modules to PLC.I want PLC to communicate with PC with wireless xbee modules.
For the same I need to change the configuration setting to 7 Bits-EVEN parity-1 Stopbits

I am using xbee s1,s2,s2b,s2c modules

The modules you are using do not support 7 data bits. They only support 8 data bits.