Dear Aleksandar,
Apologies for the very delayed response.
Please note that there is no need to "delete" a station in OSCAR/Surface to create another one located in the same city.
Currently, OSCAR/Surface doesn't allow two stations to have the same name, but that constraint is about to be lifted in the next release (1.6.0) of OSCAR/Surface which will be available very soon.
On the other hand, a solution, that is adopted in various countries, could be to add a few letters (or a word) to the name of city to allow distinguishing several stations located in the same city, for example, Kavadarci-North, Kavadarci-South, Kavadarci-Centre, etc, or something similar, if that makes sense in your national network.
Finally, when creating a new station, the inserted coordinates should be as accurate as possible.
Thank you, best regards,
Luis