There are a few different solutions. The most basic is to create a Summary data table, specifying to find the Maximum value of the measurement column, By subject ID.
Tables==>Summary
You can also use the Tabulate Platform to create a report where you place the SubjectID as a grouping row or column, and then dragging the measurement variable into the table, specifying to find the Maximum
Analyze==>Tabulate
A new column could also be created where you would specify a formula for the column, where the formula is
Col Maximum(measurment column, subjectID)