How to change modulation of examples/digital/ofdm/benchmark_rx.py dynamically

Hi all,

I am testing benchmark_rx.py in examples/digital/ofdm/ directory. I want
change the modulation method dynamically when the flow graph is running.
On
way is that lock, disconnect, reconfigure, connect and then unlock flow
graph. However, this way is often lead to program stuck. So is there any
way else to change the modulation dynamically?

Regards,

Yubo