Recently my car a W-140 '92 300SEL went in for an ATF change. The next day after reaching my work place I notice ATF seeping onto the exhaust manifold and started to burn-off. Is there an over flow valve to drain-off excess fluids after ATF change thereby causing seepage and burn-off?

Sounds like the transmission is overfilled. If you check the level cold it should be about 10mm below the low/add mark if filled to the proper level.

If it was ok before, they may have over torqued the pan bolts when the changed the fliud or not tightened them up all the way. They could have overfilled the tranny too. I once took my Mustang GT 5.0 the Jiffy lube for an oil change and they overfilled it 2-3 quarts. The engine was smoking and running terrible. I checked the dipstick and it was way over the full mark. I took it back and the drained a refilled it luckily there was no seal damage.