Changing coolant: to flush or not to flush.

Hi to everybody,
I am about to change the coolant for 2002 corolla.
Do I need to flush the system before?
I haven’t found much saying about it in manual.

Thanks,
-m.

usually u will not have to flush...just top it off...u usually flush it out every 4-5 years just so u can replace the coolants rust inhibitors...