UserForm to Return the MAX date in a TextBox resulting from VLOOKUP in ComboBox

[infinity]

p45cal and SamT, thank you for your help but it still is not working. I am at the point where I am going to give up on this process and try and find another way to get the results I am trying to accomplish. I greatly appreciate all your help.

See P45cal's post # 14

I have poured over the doc that p45cal sent me, I guess I just don't understand what I am doing wrong.

Replace everything from ApptDateTextBox.Text = IIf(MaxDate = 0, "", MaxDate) down with:

I have also replaced everything as you suggested from ApptDateTextBox.Text = IIf(MaxDate = 0, "", MaxDate) down with:

 NextAppDate = IIf(MaxDate = 0, "", MaxDate)
     If Not WeeklyIntervalTextBox = "" Then
           NextAppDate = DateAdd("ww", CDbl(WeeklyIntervalTextBox), NextAppDate)
     End If

     ApptDateTextBox.Text = NextAppDate
End Sub

... and it still is only returning the date of the currently scheduled most in the future, which was step one that you helped me with. This is what I have up to this point, but I am about to try and find a different way of doing this.

Private Sub SchoolNameComboBox_Change()


        Dim SchoolNames  As Variant
        Dim SchoolDays As Variant
        Dim i As Long
        Dim MaxDate As Date
        Dim ThisName As String
        Dim NextAppDate As Date
        Dim Weeks As Double
        
            Sheets("Future Appointments").Select
                ActiveSheet.Unprotect Password:="KingJesus1996"
                    ThisName = SchoolNameComboBox
                        With Worksheets("Future Appointments")
                            SchoolNames = Intersect(.Range("A2").CurrentRegion, .Range("A:A"))
                            SchoolDays = Intersect(.Range("A2").CurrentRegion, .Range("F:F"))  'Edit to fit
                        End With
                    
                        For i = LBound(SchoolNames) + 1 To UBound(SchoolNames) '+1 to skip headers
                           If SchoolNames(i, 1) = ThisName Then MaxDate = Application.Max(MaxDate, SchoolDays(i, 1))
                        Next i
     NextAppDate = IIf(MaxDate = 0, "", MaxDate)
     If Not WeeklyIntervalTextBox = "" Then
           NextAppDate = DateAdd("ww", CDbl(WeeklyIntervalTextBox), NextAppDate)
     End If


     ApptDateTextBox.Text = NextAppDate


End Sub

Looking at the doc that p45cal sent me, I guess I am just over my head with this and cannot figure out if the order of arguments is correct or if the data type for each argument is correct.

Either way, thank you for the help you have provided.