There's no way to know how far the knob and tube wiring goes, if it's in the attic it's probably throughout the house, and you can't just replace "some" of it; you would have to replace the entire line from panel to end. So it might be very expensive if you don't see the entire line exposed.
I'd balk at that request and tell them you won't do anything, that's not a small request, and it could be very expensive, i.e. 10,000$ to replace a bunch of circuits, tearing walls apart. But it's very hard to say without any more details about the house, pics etc...
You'd be better off abandoning the knob and tube wiring and running entire new wires. Point is you can't replace just "part" of the knob and tube wiring circuit, it's everything or nothing. With that said I'm not an electrician and could be wrong, but that's how I see it.
I'd balk at that request and tell them you won't do anything, that's not a small request, and it could be very expensive, i.e. 10,000$ to replace a bunch of circuits, tearing walls apart. But it's very hard to say without any more details about the house, pics etc...
You'd be better off abandoning the knob and tube wiring and running entire new wires. Point is you can't replace just "part" of the knob and tube wiring circuit, it's everything or nothing. With that said I'm not an electrician and could be wrong, but that's how I see it.