Next without for error in macro

I have code for a button that works aI would like to add an If statement that only changes the text in that cell if it already equals a specific value,
the orriginal code is:

 Sub Button1_Click()
Dim WS_Count As Integer
 Dim I As Integer
 Dim WS_Name As String
    
 WS_Count = ActiveWorkbook.Worksheets.Count
 
 For I = 1 To WS_Count
    Sheets(I).Select
    ActiveSheet.[E71] = "BASE_***_UP"
    Next I
End Sub

i tried

WS_Count = ActiveWorkbook.Worksheets.Count
 
 For I = 1 To WS_Count
   
    Sheets(I).Select
    If ActiveSheet.[E71] = "BASE_***_DN" Then

    ActiveSheet.[E71] = "BASE_***_UP"
    Else

    Next I

But it keeps giving me the error "Next without For"