<p>I am a first smester transfer student and my intended major is econ. I am taking econ100a, stat21 and an AC class. However, I did very bad for my mid terms. I am considering political econ for my back up major. There is a more prereq class which is IAS45 for me. Can I take it next smester and declare political econ at the end of next semester? I know there will be registration block if I dont declare a major when i completed 90 units( incliding class in progess). At the beginning of next semester, i will have more than 90units.what should i do now?</p>