Two things to clarify here. (One of them I think you arleady know)
- If there are only two members of the partnership or multi-member LLC and one is resigning, then the partnership no longer exist and must be dissolved. A partnership or multi-member LLC can not continue to exist with only one owner/member. Period.
- If the EIN was registered under your SSN and you are the one leaving the business, then that EIN has to be retired forever. Otherwise, if the EIN was registred under the other person's SSN and they will retain ownership of what will now be a single member LLC, they can continue to use the same EIN but will need to notify the IRS of a business structure change from multi-member LLC reported on 1065, to a single member LLC reported on SCH C as a part of the remaining owner's personal 1040 tax return. Hopefully they know how to correctly transfer inventory and assets so that there share of asset depreciation from the now-defunct partnership is properly accounted for.
