Solved : Update on a valid time state table is not allowed without specifying a ValidTimeStateUpdateMode

How To Solve Error : 

Cannot edit a record in Position hierarchies (xyz). Update on a valid time state table is not allowed without specifying a ValidTimeStateUpdateMode.

select forUpdate * from xyz where xyz.recid== _RecId ;

try {

ttsBegin;

_Value= “Abcd”;

xyz.Name = _Value;

xyz.validTimeStateUpdateMode(ValidTimeStateUpdate::Correction);

xyz.ValidFrom =today();

xyz.ValidTo=dateMax();

xyz.update();

ttsCommit;

}

catch

{

ttsAbort;

}