If you get rejected from a CSU, but did well senior year of high school, can colleges change their mind?

They accept students with SAT scores slightly below 1500, so if you got denied, your only real option is a community college.

No. If you are rejected from a CSU, you cannot challenge it based on your senior grades. Most of your high school isn't up to admission standards and CSUs are suffering so much from budget cuts that they cannot afford to take students who do not meet the requirements. They are denying thousands of qualifying freshman who meet the minimum requirements and the in-service-area applicants even though they should get in. The problem is that there are too many budget cuts toward higher education in California.

If you get rejected when you apply your senior year, go to a community college in California and complete either the CSU GE or IGETC at your community college to do your general education and then use www.assist.org to find your pre-major requirements for the major and CSU(s) that you want to transfer to and complete them at community college.

Nope.

Go to a community college for a year and do well, and you might be able to transfer.

not the one you got rejected from, but others can

No. But maybe next year.