You can, but there is a risk of any disease picked up by the first crop being passed on to the second.
I wonder if the risk is overrated. What is the difference in disease risk between having two succesive crops of the same family in one bed over one season compared to having one crop in a bed for the entire season? If you plant first earlies you are harvesting them after about 10 weeks, maincrops are harvested after 18 weeks or a bit longer, so two successive crops of first earlies are occupying a potato bed for about the same time as one crop of maincrop.