I have a code snippet that I am using to change the properties of a cell:

With Range("FirstSlaveCell")
.Interior.Pattern = xlGray50
.Locked = True
.FormulaHidden = False
.Validation.InCellDropdown = False
End With

I want to replace it with a function/sub that looks like the one below but I
am getting a Run Time Error 424 Object Required. What am I doing wrong?

DisableCell (Range("FirstSlaveCell"))

Sub DisableCell(rng As Range)
With rng
.Interior.Pattern = xlGray50
.Locked = True
.FormulaHidden = False
.Validation.InCellDropdown = False
End With
End Sub