I need to amend my tax return to put that I was claimed as a dependent partially for this year so my parents can successfully file their taxes

[MaryK4]

See How to File an Amended Tax Return with the IRS.  

[VolvoGirl]

You can't claim it partially.  You were a dependent for the whole year or not.  Did your parent's return reject because you claimed yourself?   Sorry but amending won't clear your ssn.  They will have to print and mail their return even if you amend. 

Or you don't qualify as a dependent and they need to delete you from their return.   Then they can efile.  You might not qualify anymore.

Here are the rules for claiming a dependent.  Do you qualify as a dependent?

https://ttlc.intuit.com/community/credits-and-deductions/help/who-can-i-claim-as-my-dependent/00/267...

And See IRS Publication 501 starting on page 11 bottom Dependents

https://www.irs.gov/pub/irs-pdf/p501.pdf