With all due respect, a forum might not be the place to get your info from.
Inform at your national CAA.
I can only speak for my national CAA's rules but I am pretty sure they're a direct copy+paste from the EASA part FCL and other relevant annexes.
Your ATPL(A) exams will supersede your PPL(A) exams
if and only if you
have succesfully completed all of your exams and thus posses an
ATPL theoretical knowledge certificate.
If you change from an integrated to a modular flightschool, with
incomplete ATPLs you will need to
adhere to the modular student requirements. Effectively meaning that you will be required to posess a PPL license
before you can finish your remaining ATPL subjects --->
your thusfar completed ATPL exams will not be counted towards your PPL theoretical knowledge certificate, you will still need to complete ALL PPL subjects as required for issueing your PPL license.
Hence my advice; stay at your current (integrated) school untill you've completed all of your ATPLs. If you revert to modular now and silently complete your exams while being administrated as a modular student without a ppl license, you will not comply with the modular requirements and
your results might be rendered invalid by your CAA.
Don't take a risk
- Inform at your national CAA.
- If the above information applies, stay integrated or make sure you can finish both PPL + remaining ATPLs within the required 18 month timeframe.