What equation shows how the cation of C6H5NH3+ acts like an acid?

#C_6H_5NH_3^(+)(aq)+H_2O(l)-> C_6H_5NH_2(aq)+H_3O^+(aq)#

For a substance to act as a Bronsted Lowry acid, it has to donate a hydrogen ion #(H^+)# , which is what it does in the equation above