FAA PPL issued based on my current JAR ATPL
Due to the different formats an EASA Licence has a (slightly) different
number to a JAR Licence.
Might I suggest you should first obtain your EASA ATPL otherwise,
when you do convert, your FAA PPL will no longer be valid and you
would need to go through the process of getting it issued again; this
time based on your EASA ATPL.
Of course you would need a valid Class 1 Medical in order to apply
for an EASA ATPL.