Amphoteric oxides possess:

Some metal oxides react with both acids as well as bases and produce salt and water. These metal oxides are known as 'amphoteric oxides'. 

For example: Aluminium oxide is an amphoteric oxide.

${\mathrm{Al}}_2{\mathrm{O}}_3+6\mathrm{HCl}\to 2{\mathrm{AlCl}}_3+3{\mathrm{H}}_2\mathrm{O}$

${\mathrm{Al}}_2{\mathrm{O}}_3+2\mathrm{NaOH}+3{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{NaAl}{\left(\mathrm{OH}\right)}_4$