If that code is running from a form which has a control named Actual_Redemption_Date, then Me!Actual_Redemption_Date should returns the control's value to your expression.

In that case, I don't see what purpose the
pActual_Redemption_Date parameter serves.

In one of your previous versions of the question, you indicated you intended to run the function as part of a query. If that is still your intention either:

1. pass Actual_Redemption_Date to the function as the pActual_Redemption_Date parameter.

Or:

2. if you want the function to reference the value of a control on a form, change Me!Actual_Redemption_Date to Forms!YourFormName!Actual_Redemption_Date