If the ONLY thing that has changed between the two planned flights is the cruise altitude then the answer is "No", because if the takeoff weight is the same, then the minimum required thrust to meet the takeoff requirements is the same.
In general, however, you would usually need less fuel for a higher altitude cruise (assuming you aren't planning to cruising at an excessively high altitude on a short route); therefore if the flight were replanned to optimise the fuel load, you would expect to have a slightly lower fuel load for the higher cruise.
Since the landing conditions will be the same, less fuel required means less weight at takeoff. So the FL400 aircraft will be slightly lighter at takeoff.
That would mean that you could use slightly less thrust for the takeofff for the FFL400 mission, IF you replanned and optimised the fuel.