Clear SDA field

Perhaps this is an issue that has long been discussed somewhere. I have searched for it but still could not find the solution anywhere. In our environment, we send a container of SDA objects to UCR from HealthConnect. To populate the container we do a SQL query on a source system and then populate the appropriate SDA objects. Sometimes it happens that I want to do an update of a field and I want to empty the corresponding SDA field. In other words, send an empty string. The Alert.toTime field of the object in question is filled with the date '2022-11-29Z13:00:00'. I have tried the following options in Objectscript :

1. set Alert.ToTime = "" 

This ensures that the corresponding <toTime> element is not sent along in the container at all. The result in ODS is that Alert.toTime is not modified and keeps its value.

2. set Alert.ToTime = """""" (6 double quotes)

This causes the corresponding <toTime> element to be passed <toTime>"<toTime> -> single double-quote as follows. The result is then in ODS that Alert.toTime is not modified and thus retains its value.

3. set Alert.ToTime = "&quot;&quot;" 

This causes the corresponding <toTime> element to be passed <toTime>&quot;&quot;<toTime> The result is then in ODS that Alert.toTime is not modified and thus retains its value.

How can I empty an SDA field?