Del. Code tit. 8 § 135
The registered agent of 1 or more corporations may resign and appoint a successor registered agent by filing a certificate with the Secretary of State, stating the name and address of the successor agent, in accordance with § 102(a)(2) of this title. There shall be attached to such certificate a statement of each affected corporation ratifying and approving such change of registered agent. Each such statement shall be executed and acknowledged in accordance with § 103 of this title. Upon such filing, the successor registered agent shall become the registered agent of such corporations as have ratified and approved such substitution and the successor registered agent's address, as stated in such certificate, shall become the address of each such corporation's registered office in this State.
8 Del. C. § 135