It appears that both .cp and .aggr files originate and are used by Adobe Captivate and if any program could convert one to another it would be this software. Unfortunately, we haven't really find anything specific about cp to aggr conversion, so it may not be possible or make sense.
Convert Adobe Captivate project file to Adobe Captivate Aggregator file.
We found 2 software records in the database related to .cp to .aggr file format conversion.
Microsoft Windows software - convert cp to aggr on Windows
Industry-leading elearning authoring software
Convert from cp 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 cp to aggr. 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.
Apple macOS / Mac OS X software - convert cp to aggr on OS X
Mac version of Adobe's e-learning authoring software