D_T This would be on the request but you could try to change it to the response as well which would require replacing "HTTP_REQUEST" with "HTTP_RESPONSE" in the above iRule or you can combine them together. Please keep in mind that the values with "old-cookie-name" and "new-cookie-name" should be replaced with the cookie you are searching for, old-cookie-name and the new cookie name which is new-cookie-name in the example.
when HTTP_REQUEST priority 500 {
if {[HTTP::header exists "old-cookie-name"]}{
HTTP::cookie insert name "new-cookie-name" value [HTTP::cookie value "old-cookie-name"]
}
}
when HTTP_RESPONSE priority 500 {
if {[HTTP::header exists "old-cookie-name"]}{
HTTP::cookie insert name "new-cookie-name" value [HTTP::cookie value "old-cookie-name"]
}
}