Length of Service based on Rehire date calculation

Content

I am trying to calculate Length of Service based on employee's latest hire date. I used Workforce Event Real Time subject area to calculate the rehire date (using action reason/action type= rehire an employee); however, I get multiple lines for each employee if they have more than one hire date. Please advise on how to remove the old hire date from the report if they were rehired 

Version

20B

Code Snippet

<saw:report xmlns:saw="com.siebel.analytics.web/report/v1.1" xmlns:sawx="com.siebel.analytics.web/expression/v1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlVersion="201201160">
   <saw:criteria xsi:type="saw:simpleCriteria" subjectArea=""Workforce Management - Worker Assignment Real Time"" withinHierarchy="true" queryDimensionality="true">
      <saw:columns>
         <saw:column xsi:type="saw:regularColumn" columnID="ccc04c383a2d7c138">
            <saw:columnFormula>
               <sawx:expr xsi:type="sawx:sqlExpression">"Worker"."Person Number"</sawx:expr></saw:columnFormula></saw:column>
         <saw:column xsi:type="saw:regularColumn" columnID="c97a1bd86184c222a">
            <saw:columnFormula>