how do you reduce acetylsalicylic acid to phenol?

Answer 1

The classic decarboxylation reaction is typically used, usually with a substituted compound.

The only reason I know to produce phenol from aspirin is that aspirin is readily available and phenol can be used to make picric acid (tri-nitrol phenol).

This is not a wise move. Crystallizing picric acid detonates too easily. It is the cause of many injuries done to amateur chemists every year.

Answer 2

Look up decarboxylation.