Need help to understand the irule

To update the Host header value without redirecting the client to the new Host value, you can use HTTP::header replace Host “csk-net-bw.aci.network”. This update will only affect the request to the pool member. The client will not see the update unless the web application uses the requested host header value to generate response headers and/or content.

if {([string tolower [HTTP::host]] equals "csk-net-corp.aci.network")}{
HTTP::header replace Host "csk-net-bw.aci.network"
}

 In 2nd request, traffic are served by different group of pool member if condition matches. URL will be remain same csk-net-corp.aci.network

if { [HTTP::path] starts_with "/test/network" } { pool P_CSK_NET_5001
}