Building is and has been medical zoned. It already has signage. No structural changes need to be made to the sign, just the face/panel needs to be changed to the new medical practice name that is going to be represented in the building. What is my recourse if the city doesn't allow the change (signage is not inappropriate or gaudy or anything...just a name change)? Doesn't make any sense that a new owner couldn't change the sign to represent his business, but would have to keep the old signage representing a business that doesn't exist there anymore!
You are correct that the facts as you have described do not make sense. I assume that you made an application to the City to change the name on the sign for purposes of this answer. If an application to paint a sign and change the name on a sign is required in the City/County and you have not submitted a formal application, then you need to submit that application.
There are factors which can impact the statutes and ordinances relating to signage. For example, if you are in a coastal zone area, there are special rules you must follow to obtain a Coastal Development Permit.
If the City has an ordinance related to signs, there should be an approval on file with the City for the existing sign. You need to get a copy of the approval of the sign and review the specific conditions of approval attached to the signage permit.
In short, the immediate steps you need to take are:
1. Obtain the permit for the existing signage from the local jurisdiction;
2. If applicable determine whether or not the local jurisdiction or the coastal commission have jurisdiction regarding the signage;
3. Determine whether the local jurisdiction requires a permit to paint and to change the name.
4. If the answer to number 3 is yes and you have not filed for a permit, then file for the permit.
Good luck with your signage!
If all you are doing is changing the wording on an already existing sign, I don't think you even need to apply for a permit. I would go ahead and make the change and see what happens. Before doing that, check the city's rules on signage to make sure you aren't in any violation.
If you have already applied and been rejected, there are any number of reasons why the city might do that. More information would be needed to give you a complete answer.
I'm guessing the sign was legal and permitted when installed, but the ordinance was changed to regulate signs more stringently (for instance, to reduce the allowable size of the sign in square feet, or to reduce the number of signs allowable on buildings or even to disallow backlighted plexiglas signs in boxes). Then when the last permittee left, the sign was not "grandfathered" but required to conform to the new ordinance.
Typically, unlike other, more substantial uses of land, sign ordinances require non-conforming signs to be "amortized" (i.e., depreciated) and removed after X years or when a change in ownership or signage occurs, that is, unlike the principal buildings or uses of land which are "prior, non-conforming uses", they are NOT "grandfathered" and allowed to legally continue.
I'm guessing your sign doesn't conform to the current ordinance. Talk to the building department or look up the local zoning ordinance (sometimes they are even on the city's website these days). Or apply for a permit, and you should be able to clear up this apparent mystery quickly. Or call a sign company which fabricates and installs signs locally, they probably have a good handle on what the problem might be.