ewb to ms14 conversion covers the export between two formats from NI Multisim, in case .ewb file from the ancestor of the modern software called Electronic Workbench.
We have not found any specifics about this data exchange, beyond the fact that both file types are or were at some point supported in the software.
Most sources claim that .ewb files can be still imported to Multisim, but saving to .ms14 file is most likely possible only with specific version of MultiSim, in this case version 14. This is because Multisim does not offer backward compatibility, meaning later versions are unable to save to previous formats.
It is unlikely any 3rd party software can otherwise help you convert ewb to ms14.