I was recently accepted to UC Berkeley (UCB) and wish to accept their offer; however, back March I completed my SIR for UC Santa Cruz (UCSC). I understand that one cannot SIR to two UCs, but I wish to rescind my SIR at UCSC in order to SIR at UCB. I was at a UCLA Transfer Day yesterday, and an admissions official replied to the very question I about to purpose, by stating very simply and matter of fact, “Just cancel your SIR at the other UC, and SIR UCLA.” What is the process? IS it that simply?
Email admissions at UCSC stating you wish to withdraw your SIR. You will lose your deposit at UCSC however.
Yes it’s tat simply.
Thank you Gumbymom. That places my mind a bit more at ease. 
Gumbymom. May I submit my SIR at Berkeley now or should I wait until UCSC has processed my rescindment? I am very anxious about this whole process.
Email admissions this weekend. Call Monday to make sure they have recieved your email and acknowledge they have cancelled your SIR at UCSC, then SIR to UCB.
Thank you Gumbymom 
I am drafting my letter now. I initially mentioned Berkeley as the “other institution”, then switched it to “Berkeley”. Should I be ambiguous, as the two institution are part of the same UC System? I feel being forthcoming is the proper thing to do.
@Deutschboy Just go online. At ucsc there is a place to cancel your SIR. It’s in your portal somewhere. If you can’t find it and contact admissions, you don’t need an explanation. Simply give them your name and UCSC ID and say you wish to cancel. People switch all the time.
You can also SIR to berkeley now and cancel ucsc after.
Lindyk8. Thank you :">