For some reason I thought is was possible to amend a booking to add a connecting flight. But if that is not possible, I will have to re-think.

No J seats left on that flight or any other to SFO within a week. And I would hate to cancel and re-book for a week earlier; I have already paid to select our seats and would lose the whole payment for that ($362) in addition to the $110 in cancellation fees.

Of course we will lose all that anyway if we decide to cancel the whole trip, which is also a possibility. . . . I will just wait a month or so and see how things are going, before I make any changes.

And if we decide to keep the trip, it looks like our best option may be to book a separate flight from Milan to LHR the previous day, or maybe even earlier? We are trying to avoid a stopover in the UK as it complicates the testing, etc. for our return to the USA. An airside transit would avoid that, at least under the current regulations.