The short answer is that you can't, but if you are running the code from Outlook (from which the FileDialog(msoFileDialogFilePicker) is not available in VBA, you could use one of the Office apps that does to provide it. This means a small delay while the app opens, but it works well enough. Call the following function with the filepath you wish to start from e.g.
Sub test()
MsgBox BrowseforFile("C:\Path\")
lbl_Exit:
Exit Sub
End Sub
If you are running the code from some other app, such as Excel (used here to provide the dialog) you don't need to Create or Get the object as you already have it.
Public Function BrowseforFile(strPath As String) As String
Dim xlApp As Object
Dim fdFolder As Object
Dim bStarted As Boolean
On Error Resume Next
Set xlApp = GetObject(, "Excel.Application")
If Err <> 0 Then
Set xlApp = CreateObject("Excel.Application")
bStarted = True
End If
On Error GoTo 0
xlApp.Visible = False
Set fdFolder = xlApp.FileDialog(msoFileDialogFilePicker)
With fdFolder
.Title = "Select file and click OK"
.AllowMultiSelect = False
.InitialFileName = strPath
.InitialView = msoFileDialogViewList
If .Show <> -1 Then GoTo err_Handler:
BrowseforFile = .SelectedItems.Item(1)
End With
lbl_Exit:
If bStarted Then xlApp.Quit
Set xlApp = Nothing
Exit Function
err_Handler:
BrowseforFile = ""
GoTo lbl_Exit
End Function