Canada & the USA have mutually come up with a process to convert one licence to the other.
To go from Canada to the USA I know that one just needs to write a single exam and all your endorsements etc get transfered to the same level of licence e.g. ATPL-Aeroplane --> ATP-Airplane
https://www.gleim.com/aviation/ gives a course for the canadians. I do not know if there is a similar course for the americans to use.