Several programs including EndNote itself should be capable of conversion various citation entries like RIS and save them in EndNote's default ENW format.
Convert Research Information Systems citation to EndNote citation file.
We found 5 software records in the database related to .ris to .enw file format conversion.
Microsoft Windows software - convert ris to enw on Windows
Search tool for online bibliographic databases
Convert from ris file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned ris to enw. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Bibliographic reference and citation management software
Apple macOS / Mac OS X software - convert ris to enw on OS X
Application to organize bibliographies
A bibliography manager for Mac
Apple iOS (iPhone, iPad, iPod Touch devices) software - convert ris to enw on iOS
App for iPad used to search in bibliographic databases