With the engine on, pull up by hand on the window's "down" side -- you will often feel it move back into position, then raise it. If that isn't sufficient, with the engine still on, push against the glass from the outside, near the top where it is off-track, then raise it. Sometimes you need to do that more than once to get it completely back into position. This solution usually works, with no more trouble for many months, but it is not a permanent solution.

Finally bought a honda and it has been a pain in the posterior! Staying with domestics from now on.