The SFO flight is still there. CX872 depart on 1st July 0045am from HKG. Not sure what is your original flight though.

But the problem is that the flight from SIN CX636 arrive at 0015am on 1st July. So can’t make the connecting flight. Thus CX is not selling this connection.

And for SQ, they did not reinstate SFO at all. So far, they have been sending email to paxes for official cancellation around 21 days before the flight. Although they did announce that most flight are cancelled before that.