There is plenty of info on here, this question was covered as recently as last week, suggest you use the search function...?
Try here for a start
https://www.pprune.org/north-america...gulations.html
In short, there is no conversion, you need to simply follow the requirements to gain the FAA ATP listed in 14 CFR part 61A
person who is applying for an airline transport pilot
practical test must meet -(i) The
eligibility requirements of
§ 61.153; and(ii) The aeronautical knowledge and
aeronautical experience requirements of this subpart that apply to the
aircraft category and class
rating sought.
https://www.law.cornell.edu/cfr/text/14/61.153
https://www.law.cornell.edu/cfr/text/14/61.159