I'm assuming that you mean the -1 or -2 is part of the filename, rather than replacing the .pdf extension. (myname-1.pdf rather than myname.-1 or myname.pdf.-1)
Code:
Private Sub ControlNumber_DblClick(Cancel As Integer)
Dim TheFile As String
Dim TheNumber As String
Dim FileExt As String
Dim thepath As String
thepath = "Q:\Data\ServiceDatabase\worktickets\"
TheFile = ControlNumber.value
TheNumber = "-" & {{{{This is where you code which of the files you want to get... 1, 2, 3 etc}}}}}
FileExt = ".pdf"
Application.FollowHyperlink thepath & TheFile & TheNumber & FileExt
End Sub