What about this process must be altered to ensure the organelles remain in the keratinocytes?

Answer and explanation;

The melansomes are taken up from the extracellular space, so the process would either be receptors-mediated endocytosis or phagocytosis. Both of these processes send the cargo to the lysosome for destruction, so if the organelles are to remain in the keratinocyte, this final step must be inhibited.

Melanocytes are cells of neural crest origin. In the human epidermis, they form a close association with keratinocytes via their dendrites. Melanocytes are well known for their role in skin pigmentation, and their ability to produce and distribute melanin has been studied extensively. Keratinocytes play an important role in providing skin structure and in functioning of the immune system.