Filament Flow Rate Control


I am currently using a TAZ 4 printer. But, I am not able to find an option for the flow rate control of the filament. Is it at all possible to change the extrusion rate of the filament or is it preset?

If it is indeed preset, where can I check the preset extrusion rate?

Thanks a lot for the help, in advance.

Best Regards,
Harsha Bharadwaj