How can I enable and disable NAT rule throught console?

Hi there

I have 2 public IP.
One of then, I set in the red interface, like aaa.bbb.ccc.ddd.
The other IP I set in blue interface.
So the default IP is one set in red.
But I need that some internal host use the default for two hours and then change to use the blue interface public IP.
I have create a NAT rule that works fine. It’s looks like this:

iptables -N NAT_SOURCE
iptables -t nat POSTROUTING -j NAT_SOURCE
ptables -t nat -A NAT_SOURCE -s xxx.zzz.yyy.www/32 -j SNAT --to-source aaa.bbb.ccc.eee

My question is: how can I disable and reload the firewall rules throught console?
My goal is to create a crontab to disable the about rules every 2 or 4 hours.