ICAO the ultimate answer !
There is no such thing as an ICAO PPL, CPL or ATPL. The International Civil Aviation Organisation does not issue licences. Most countries with state or joint state authority that do, are already accredited and in conformity with the ICAO. If you want to convert your licence from that issued or validated by one country to another, you will need to contact that countries aviation authority for the terms it deems sufficient to satisfy its own requirements.
From the ICAO website :
"ICAO does not issue any licences. Licences issued by ICAO Contracting States on the basis of Standards and Recommended Practices of Annex 1 – Personnel Licensing, are habitually called ICAO licences. This has led many to believe that there is a specific ICAO or international licence. The fact is that there is not one single international licence issued by ICAO or any other organization. States issue their own licences based on national regulations in conformity with Annex 1 specifications and validate licences issued by other Contracting States on the basis of bilateral or multilateral agreements or the fulfilment of nationally legislated requirements.