Reveresal of values Query

I need a query to update the value at the point from which the metrics rises or decreases .For example I have a table with

ID METRICS INDICATOR

1 204.4

2 205

3 206 H

4 204

5 199

6 198 L

7 204

8 205 H

9 201

10 199

If you see the above table the metrics column the reversal of metrics happens . The point the reversal happens should be updated with the indicator value H/L as shown in the indicator column.

Thanks