Tax Year Prior to 2020: I filled my tax returned but I put it as someone could claim me but no one can claim me. How could I change that so I may receive my stimulus check?

If you qualify to be a dependent, you are not eligible, regardless of if someone claims you or not.

Taxpayers likely won't qualify for an Economic Impact Payment if any of the following apply:

• Your adjusted gross income is greater than
  • $99,000 if your filing status was single or married filing separately
  • $136,500 for head of household
  • $198,000 if your filing status was married filing jointly
• You can be claimed as a dependent on someone else’s return. For example, this would include a child, student or older dependent who can be claimed on a parent’s return.
• You do not have a valid Social Security number.
• You are a nonresident alien.
• You filed Form 1040-NR or Form 1040NR-EZ, Form 1040-PR or Form 1040-SS for 2019.

I couldn't be claimed as a dependent because I was not a full time student and I made too much money.  So how can I change my status to get the stimulus check

One option available to you is to consider amending your return. However, this takes another 12-15 weeks to get processed. That actually defeats the purpose as I'm sure you are hoping to receive your stimulus check soon.