RQA GPvP Committee
without having the full details of this AE, it does sound as if it should have been reported as "serious", once the surgery occurred (we presume trial participant will be hospitalized, why the delay of 3 months is not clear).
The event you describe is rather borderline, because the surgery decision was made, but the actual surgery (which then leads to the upgrade to serious AE) would be delayed until after the end of the trial participation for that patient.
Most companies would take a conservative approach (i.e. report as serious, follow-up information) and update their clinical trial database (already enter a comment that hospitalization is planned due to the initial AE).
Practically, most companies would only actually upgrade to serious, once the surgery then had actually happened (in case the patient recovered prior to the surgery).