#cat -n file
 1  POLY_STATS
     2  {
     3  EqName 103_tri
     4  Id 123
     5  act_polyCount 1
     6  act_polyValue 0
     7  }
     8  POLY_STATS
     9  {
    10  EqName 103_tri
    11  Id 123
    12  pass_polyCount 2
    13  pass_polyValue 0
    14  }
    15  POLY_STATS
    16  {
    17  EqName 103
    18  Id 123
    19  mes_polyCount 2
    20  mes_polyValue 0
    21  }
    22  POLY_STATS
    23  {
    24  EqName 504
    25  Id 123
    26  mes_polyCount 2
    27  mes_polyValue 0
    28  }
    29  }

 sort file | uniq -c | grep EqName|gawk '$1==2{print $3}' #Get the value of Eqname,which is repeating twice
 cat -n file|sed -n '/103_tri/p' #get line number where EqName is coming twice
 From=$(cat -n file|sed -n '/103_tri/p'|awk '{print $1}'|tail -1)
 echo $From #10
 From=$(echo "$From + 2" | bc)
 To=$(echo "$From + 1" | bc)
 sed -n $From,${To}p file # Printing the lines from the second block which i want to move to the first block

pass_polyCount 2
pass_polyValue 0