This really depends on your school and what the MS Degree is in. A friend of mine started as an MPH student and switched to the MHA program in his second year. However, although there was some overlap, he did have to stay an extra semester. Bear in mind that many MHA and MPH programs may have 2 or 3 classes in common but the rest are not. With respect to your MS degree, look at the coursework. If the coursework is similar then it might be easier, however if it is not then you might have to stay in school longer. Talk to an advisor and see what the admissions committee says as well. Sometimes the admissions committee will hinder the process rather than the actual coursework.
