Determine if Worksheet Exists

[scgamecock]

I have the following Code:

With ActiveSheet
        LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
    Worksheets(2).Select
    Range("A1:F85").Select
    Selection.Copy
    Sheets(1).Select
    Range("A" & LastRow).Select
    ActiveSheet.Paste
    Range("A1").Select
    End With
    
    With ActiveSheet
        LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
    Worksheets(3).Select
    Range("A1:F85").Select
    Selection.Copy
    Sheets(1).Select
    Range("A" & LastRow).Select
    ActiveSheet.Paste
    Range("A1").Select
    End With
    
    With ActiveSheet
        LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
    Worksheets(4).Select
    Range("A1:F85").Select
    Selection.Copy
    Sheets(1).Select
    Range("A" & LastRow).Select
    ActiveSheet.Paste
    Range("A1").Select
    End With

I need a way to tell the macro to run only if the worksheet exist. For example, if Worksheet(4) does not exist, then I do not want that portion of the code above to run.

[jggtz]

'Declarations
Dim xls As Excel.Application
Dim xlswbook As Excel.Workbook

'Instantiate
Set xls = New Excel.Application
Set xlswbook = xls.Workbooks.Open("SomeXlsFile")

'Navigate thru all sheets
For I = 1 To xlswbook.Sheets.Count
MsgBox xlswbook.Sheets(I).Name
Next I