Final answer:
To avoid overlapping during a retouch relaxer application, apply the relaxer to the area at the end of the processing time.
Step-by-step explanation:
To avoid overlapping during a retouch relaxer application, you should apply the relaxer to the area at the end of the processing time. This ensures that the previously processed hair does not get overprocessed. Applying the relaxer to the area at the beginning or middle of the processing time can lead to overlapping and damage to the hair.