Remote Call Divert

Simple really - I can divert calls from my mobile to another number by using one of the functions on the handset menu. But this is not much help when I have forgotten my phone because it was charging overnight in the corner of the kitchen, and I rushed out without it in the morning. (I haven't really, I'm just giving an example)
There are some things that you can do on the phone company website, including a personalised login area, which I must confess I haven't really bothered with. I might be more interested if it gave me the option of diverting the calls from my mobile lying forlornly in the kitchen at home to the phone on my desk at work. (Obviously difficult to deal with non direct dial work numbers, but you could divert to the mobile of the person who sits near you, assuming they haven't left theirs at home too..!)
I don't know whether the phone companies would let you log in and actually interfere with call routing at a basic level, but at least they may be able to deal with requests in almost real-time.