If any program is capable of .rex to .rcy conversion, it would be ReCycle audio editing software from which both of these file type originate. As to whenever it is actually possible or useful to convert one to another, could not be reliably verified. However, both seems to be audio formats of some sort, so this conversion should be possible.
Convert ReCycle audio loop export file to ReCycle audio loop file.
We found 2 software records in the database related to .rex to .rcy file format conversion.
Microsoft Windows software - convert rex to rcy on Windows
Program for fast editing of sampled parts, chopping up riffs, remixing and doing mash ups
Convert from rex 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 rex to rcy. 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.
Multiplatform software - convert rex to rcy on any platform
A professional instrument conversion program