Public Sub DateToQuarter()
    Dim cell As Range
    Set cell = ActiveCell
    Dim qtrNo, Year As Integer
    Do While Len(cell.Value) > 0
        Select Case Mid(cell.Value, 1, InStr(cell.Value, "/") - 1)
            Case "1"
                qtrNo = 1
            Case "4"
                qtrNo = 2
            Case "7"
                qtrNo = 3
            Case "10"
                qtrNo = 4
            Case Else
                MsgBox "there was an error!"
                GoTo ErrorHandle
        End Select
        
        Year = Mid(cell.Value, InStrRev(cell.Value, "/") + 1, 4)
        
        cell.Value = "Q" & qtrNo & " " & Year
        Set cell = cell.Offset(1, 0)
    Loop
    
ErrorHandle:
End Sub

USAGE: select first cell in column you wish to transform, then activate macro.

This macro will run for cell below (and including) the one you selected, and it will stop when it encounters the first blank cell in the column.

note: original date string must be in "m/d/yyyy" format

Transform Date String to Quarter String

Visual Basic