The conversation between human and AI assistant.
[|Human|] Change the following sentence to the 'past perfect tense': "He had gone to the store"
[|AI|] He had gone to the store is already in the past perfect tense as it indicates an action completed before another event in the past. It cannot be changed any further.
[|Human|] 
Change the following sentence to the 'past perfect tense': "He had gone to the store"