I am in CA, just formed a single member LLC from a sole proprietorship. I have an existing EIN apart my social when I was a sole proprietor. The only name change was having "LLC" at the end of the company name. Do I need to obtain a new EIN? or can I use the existing? I do not have any employees. Do I need to do some type of name change to reflect the "LLC" or if there is no change in the body of the company name does that make a name change not necessary.
You don't need to do anything. When it comes to taxes, the only difference between a single member LLC and a sole proprietorship, is the spelling. Literally!
Just make sure which ever schedule you use in your 1040 reflects you correct business name.
As a single member LLC you generally do not need a separate EIN. See the attached discussion from the IRS:
If your LLC issues, or will even "potentially" issue a 1099-MISC or W-2 in the future, then I highly recommend an EIN. Otherwise, you will be putting your social security number on tax reporting documents you provide to employees and/or vendors that you may have never actually met and therefore do not know there. For me, I use an EIN in my single member LLC, because there is no way on this green earth that I will EVER give my SSN to one of my vendors. They get the EIN, or I don't do business with them.