These scenarios will walk you through the various ways to set null or empty values within a formula,
Scenario 1 - Clear() function
You have a formula of type 'Save To Current Record' on the Account entity and you need to set the 'Description' field to a null value if the City field equals New York.
In this scenario you can use the Clear() function to set the field to a null value while the Target Property field is set to 'Description'.
Scenario 2 - UpdateRecord() and '?'
This scenario is similar to the above but this time you need to set several fields to null. In this case the best way to achieve this is to use '?' character to set the fields to null when using the UpdateRecord() function.
This sample shows how to set to null values for text fields, optionsets, currency & lookup fields. The same process applies to other field datatypes. Please note that '?' is used internally by North52 to represent a null value.