Of course, I can not prove this, I am not a physicist. I suspect, however, that the air pressure would drop somewhat, and thereby also the greenhouse effect would be reduced somewhat.
It depends on what you mean with "switching orbit", if it means "slowly changing orbit to reach the new one" or "immediately changing orbit" then I think the current conditions of Venus would last for a lot
of time, and we wouldn't probably be able to see the changes within our lifespan.
Still, after some thermal energy have been dissipated, I guess some components of the atmosphere will slowly start to cool down and eventually drop on the surface as ice and the air pressure will decrease.