APM Irule multiple access profile for one virtual server

Semantically your code is correct, but the elseif needs to be on the same line as the if's closing bracket.

when HTTP_REQUEST {
    if { [class match [string tolower [HTTP::uri]] starts_with landing_uri] } {
        virtual [class match -value [string tolower [HTTP::uri]] starts_with landing_uri]
        log local0.info "URI = [HTTP::uri] and 1st Virtual Match"
    } elseif { [HTTP::cookie exists MRHSession] } {
        if { [class match [ACCESS::session data get -sid [HTTP::cookie value MRHSession] session.server.landinguri] starts_with landing_uri] } {
            virtual [class match -value [ACCESS::session data get -sid [HTTP::cookie value MRHSession] session.server.landinguri] starts_with landing_uri]
        }
    } 
}