Welcome IL_BMW_650. So in regrads to your question, you have to replace the lights. The rear is simple enough but the front depends on if you want to replace just the turn signal section or the whole headlight. The rear I believe you can just buy a new set along with an adapter cable to prevent flickering in the LEDs (search for this on this forum) The front LED turn signal assembly will also require some wiring modification to work as well. This too was done by members here just do a seach. So to put simply you would need new lights not just bulb replacement.
2008 650 Convertible- 6 Speed manual- Sport package- HUD- Lane Departure- Comfort Access- Merino Leather- HD Radio- SAT