Many concepts of record ownership seems to have changed recently, at least with regard to *A RTWs. It seems that any *A airline can access your entire RTW record, and they can make changes at least to their own segments. So, in schoflyer's situation, UA has access to his record (probably having to use a flight number and date rather than PNR) whether the trip has commenced or not, and UA can make changes to the date/time of any segment on UA. And any changes that UA makes will be visible to each of the other *A carriers if they subsequently pull up your record. This really has simplified the whole process (though it may also have closed a loophole or two as well).