A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data
This requires VBA, so it will only work in the desktop version of Excel, not in the online version, nor on iOS or Android.
And users will have to allow macros.
Right-click the sheet tab.
Select 'View Code' from the context menu.
Copy the code listed below into the worksheet module.
Switch back to Excel.
Save the workbook as a macro-enabled workbook (*.xlsm).
Private Sub Worksheet_Change(ByVal Target As Range)
Dim rng As Range
Set rng = Intersect(Range("C2:C" & Rows.Count), Target)
If rng Is Nothing Then Exit Sub
If rng.CountLarge > 1 Then Exit Sub
If rng.Value = "" Then Exit Sub
If rng.Offset(0, 1).Value <> "" And rng.Offset(0, 1).Value <> "Complete" Then Exit Sub
If rng.Value > Date + 60 Then Exit Sub
Application.EnableEvents = False
rng.Offset(0, 1).Value = "Upcoming"
Application.EnableEvents = True
End Sub