If the owner of the app gives away ownership it can easily be transferred to a new developer (this is the best option as users can keep using this app with improvements, but you’ll need to try and get into contact with the original owner)
or if an app is neglected enough you can also ask athom to hand over the ownership, though you of course do need a good reason for it (like it not working anymore or the support is too bad)
Normally a second app that supports the same brand is not accepted, though there have been made exceptions.
