[+phx:if=`[!UltimateParent!]`:is=`775`:then=`Reviews`:else=`Comments`+]
[+phx:if=`[*parent*]`:is=`775`:then=`Reviews`:else=`Comments`+]
Then use this:
[+phx:if=`[*parent*]`:is=`775`:then=`Reviews`:else=`Comments`+]
[+phx:input=`[!UltimateParent!]`:is=`775`:then=`Reviews`:else=`Comments`+]
[*parent:is=`775`:then=`Reviews`:else=`Comments`*]