UART baud rate change on Raspberry

Hi ,
I’ve a E220 fully working on Raspberry Pi4 at 9600 baud but I’m not able to change at 115200.

If I change the parameter (see below) on the example “send_fixed_message”

loraSerial = serial.Serial(‘/dev/serial0’ baudrate=115200, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, bytesize=serial.EIGHTBITS)

I’ve the error reporting that I cannot change the baud rate before setting.
So I first changed the configuration with set_configuration setting

configuration_to_set.SPED.uartBaudRate = UARTBaudRate.BPS_115200

and then running again “send_fixed_message” after changing the baurdate on raspberry serial port but seems not working.

Which is the correct procedure/steps to change the E220 serial baudrate on Raspberry?
Thanks in advance
Paolo