thanks for the replies

yes-- its the mfu that cant be done, there no facility for multi city/open jaw in "book and upgrade with miles"

also, previously, I havent been able to straight purchase a multi city/open jaw tkt man/US online either -- although I could do it with LHR instead of man

for man, its always crashed on the pricing page. even with separate flights-- [us1-lhr-man // man- lhr-us2 ]

havent tried that this time yet though.

thanks