I have an EIN number for an LLC that is currentlly taxed as a sole proprietorship. I want to change the LLC to a partnership with my son. Do I need a new EIN number ? How do i notify the IRS of the change?
yes you do. file a new SS-4
box 10
Changed type of organization. Check this box if the business is changing its type of organization. (including available space immediately below) the type of change made. "From sole propreitorship (LLC) to partnership (LLC)".
box 18 is "no" since the partnership has never applied for an EIN before.
In addition to @Mike9241 response to your direct question, keep in mind that there are many other items and issues that need to be addressed:
It is probably a good idea to have a one on one with a tax professional to discuss the new entity structure, how it works, what you can and can't do, etc. Best to start off on the right path.