Ok I work for CHANEL at Nordstrom in the Mall of America in Minneapolis. Here's the procedure. Only stores that carry CHANEL are allowed to process sales and returns. When you take it back to whichever store you choose in California, they will have to call the store you purchased it from and complete the return over the phone. The return will actually be completed on a register that is approved by CHANEL. Then, the next day, the bag will be overnighted back to the store that it came from.
This policy is both for CHANEL and GUCCI, which are considered luxury designers and have very specific guide lines for how their merchandise can be sold.
Nordstrom has the same procedure with Chloe. Not supposed to accept return unless they sell it at the store. Its a pain because this is not communicated to you at the point of sale (99% of the time). However, I've been able to get customer service to process the return for me. Good luck.