Macro help: Adding Message Box if Cell = certain value

[Jessica1979]

Hi, I'm a newbie to macro, and am stuck...help!

The worksheet needs to automatically pops up a warning message whenever range of cells K12 to K27 equals to 815500. I got it to partially work with the code:
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Private Sub Worksheet_Change(ByVal Target As Range)

If Range("K12").Value = 815500 Then

MsgBox ("GL Account #815500 - Training & Education: requires CEU form approved by HR and must be included for reimbursement " & ". Continue?"), vbYesNo

End If
End Sub
_____________________________________

Issue 1) macro only applies to cell K12, how do I apply to range of cells K12 to K27?

Issue 2) macro now run all the time when K12 = 815500, how do I get it to only display the message box once and stop (until the next cell = 815500 between cell range K12 to K27)?

Help...my hair's going to turn white from thinking so much...

 

[JoeMo]

What do you want to happen if the answer to the popup is Yes, and what should happen if it is No?

 

[Jessica1979]

What do you want to happen if the answer to the popup is Yes, and what should happen if it is No?

Nothing really, basically just an informative warning box, choosing yes or no results the same, can be removed.

 

[Jessica1979]

Nothing really, basically just an informative warning box, choosing yes or no results the same, can be removed.

Actually, I got it figured out!! I had to define range and selection, end the if statement, then go Next before ending sub. woo-hoo!!