  In a recent comment by Fern\'{a}ndez, it has been argued that our solution
method of an effective Hamiltonian based on the characteristic polynomial
[Phys. Lett. A 443 (2022) 128215] had been developed several years earlier by
Fried and Ezra [J. Chem. Phys. 90 (1989) 6378]. We show here several important
differences between our treatment and the resummation method proposed
previously by Fried and Ezra.
