Can I keep my EIN?

I obtained an EIN for my business in May, 2025 as a single-member LLC. In June, I added a partner to my business. I recently learned that a new EIN may be needed when changing from a singl-member to multi-member. We have used the current EIN to obtain several permits and licenses, and a new EIN may cause us to have to reapply for these. We have not had any revenue or hired any employees yet. Is it possible to keep the current EIN and change the classification or will a new one be required?