It shall be unlawful for any person, firm or corporation to alter, relocate, reconstruct or cause to be rotated, reconstructed or changed in any manner by wording or otherwise or maintain within the limits of the Borough any sign without first having obtained from the Zoning Officer and having in force and effect a permit to maintain each sign. The above notwithstanding, existing signs, whether or not conforming to existing ordinances, may be removed, refurbished and replaced.