How to create a calculated field that can be over ridden by the user if needed

Question

I've seen similar threads here but they're not exactly what I'm after.

I need a field to calculate the Annual Renewal Date of a contract (3 months prior to the End Date) and allow the user to override the Annual Renewal Date value if need be.

Brief: Field A = Annual Renewal Date (calculated value) Field A formula: =DATE(YEAR([End Date]),MONTH([End Date])-3,DAY([End Date]))

Field B = Annual Renewal Date (manual date entry)

Question: So I need field 'A' to automatically calculate the renewal date 3 months prior to 'End Date', unless Field B has a value manually entered into it by the user; in which case Field A would be hidden from the list view.

Is this possible ? I've looked all over the internet for the answer and not been successful.

Additionally, as far as I can tell I can't create a default value field (which is what I wanted to do in the first place) because the Annual Renewal Date is calculated with a field name that can't be referenced (this being 'End Date').

Open to any suggestions.

Answer 1

Why don't you use 3 columns. End date, days to renew (Number column with a default value, but you can manually enter a number..Ex 90, and calculated field which is "End date - days to notify)?

Answer 2

Wouldn't it make more sense to display either Date in FieldA

=IF( ISBLANK([FieldB])
    , DATE(YEAR([End Date]),MONTH([End Date])-3,DAY([End Date]))
    , [FieldB]
   )