declaring variables help

Public Sub SS(ID)
Dim Seat As Range
Sheets("Seats").Activate
   Range("A2").Select
       x = ActiveCell.CurrentRegion.Rows.Count
    Set Seat = Sheets("Seats").Range("A2:A" & x)
       
    SeatID = "ID"
    Seat.Find(SeatID).Select
    ActiveCell.Offset(0, 2).Value = ("1")
    Call AVF
End Sub

This code is used to book a single seat at one time. When a seat button is clicked it will call this function and this code will receive the id of the seat and will locate it on a worksheet. I have used this code before just in a different scenario and it worked. However in this case it works until one point where it can not find "Seat" that is highlighted above, even when I have declared what "Seat" is above, with the de bugger telling me that there is a "Run time error - 91: object variable or with block variable not declared" ?????