Hi Ed and Sil and welcome to Just Answer!
There is no need to change the mortgage from joint to individual in order to deduct the mortgage interest. As long as you will pay that interest from your separate funds - you will be eligible to deduct your expenses.
However - because California is a community property state - expenses paid out of your community funds are divided equally.
If you want to remove your wife's name from the mortgage - you need to contact your lender. Most likely - you will need to refinance the mortgage.
I assume that you will file a joint tax return. It would be more beneficial to file jointly because your overall tax liability will be less compare if you choose to file separately.
Also if you file separate tax returns
- you will not be able to claim some deductions
When a married couple files separate returns and one spouse itemizes deductions, the other spouse cannot claim the standard deduction and therefore must itemize to claim their allowable deductions.
Please let me know if you need help to estimate your possible tax liability.
Be sure to ask if you need any clarification.