N.C. Gen. Stat. § 28A-18-4: Service on or appearance of one binds all.

In actions against personal representatives or collectors, they are all to be considered as one person, representing the decedent; and if the summons is served on one or more, but not all, the plaintiff may proceed against those served, and if the plaintiff recovers, judgment may be entered against all. (1868-9, c. 113, s. 81; Code, s. 1508; Rev., s. 161; C.S., s. 165; 1973, c. 1329, s. 3; 2011-344, s. 4.)