TMSH modify packet-filter

I am looking for some syntax examples for modifying packet-filter rules via tmsh on the F5 (version 11.2) Our aim is to use our HP network automation tool to schedule basic rule changes in our approved out of working hours Eg. where we allow HTTP service to various virtual servers and create a new one we want to add the ip address. Obviously the syntax has to be very precise otherwise the scheduled job to make the change will fail or cause harm. Thanks in anticipation. cheers Greg