I am trying to lookup a value in a table and replace the contents of the adjacent cell.

For example I want to lookup D2 in A2:A3, and then replace the value of the adjcent cell (array B2:B3)...which in this case would be cell B3) with the value in E2. Any recommendations how to do this?

1 A B C D E
2 10 4 20 8
3 20 5