Question

our school sent up the best exhibit to the town hall.('re write using 'better')

Answer 1

The exhibit sent by our schoolto the town hall was better than any other exhibits

Answer 2

The answer is:

No other school could sent up a better exhibit than our school to the town hall.  

Here only the degree of the adjective is changed, hence the syntax is slightly changed.

From the superlative degree, (best), the sentence is written on the comparative degree (better) without changing the meaning of the sentence.

Here the subject and object has remained the same.