Convert ICAO CPL to US CPL
To convert ICAO CPL to US FAA CPC, first get FAA PPC based on foreign Licence. This requires filling up a form available at FAA website, submitting it to FAA by post or FAX. The FAA will get necessary verification from the State of issue. They would then issue a letter. You may get a FAA Private Pilot Certificate within six months from the date of issue of this letter, either from FSDO concerned or approved DPE.
After getting the PPC, appear for and pass US commercial written test. Then take flight training (minimum three hours) and get the logbook endorsement from your instructor that he/she has trained you to take the Coomercial Checkride and considers you ready for it. You may then take the Checkride.
You also need to comply with all the experience requirements stipulated for issue of Commercial Certificate in part 61, including 10 hours on complex aircraft. Of course any flying experience already gained for ICAO CPL counts.