We did this last year. It's really not that big of a deal. My best advice is to call the IRS's charitable office at 1-877-829-5500.
As per the IRS, we had to take a vote to formally change our name from Eastside PTG to Eastside PTO. Then we wrote a letter of request to the IRS, that included our charitable tax number and two board member's signitures. We also included a copy of the secretary's typed minutes that noted the vote and the name change. Finally, your by-laws will need to be updated, signed and filed with the school's business office.
Would anyone have any guidance that they would like to offer when members would like to switch from a PTA to a PTO? How do you keep your funds? What paperwork is necessary? What legal issues may we encounter? We have a PTA region director who likes to attend our group which makes this a sensitive and stressful situation. Any comments would be appreciated. All I could find on here was starting a brand new group, but I am looking for some information of switching.