Questions regarding reference type catalog variableSummary1. What is the best practice table to use or extend from to maintain the data for catalog item variables of type reference and lookups?The best practice would be to avoid any table that would contain huge amount of data. If the values are already available in Choices [sys_choice] table. The best practice is to use the Choices table whenever possible. Otherwise, use reference qualifiers to control the number of records returned.2. Is there any cost involved to extend from sys_choice table? There should not be any cost involved , but it is a better idea to have this checked with your territory manager and/or ServiceNow solution consultant.3. If a catalog item variable's reference table is changed the historical data is lost. How can I go about retaining the values in the variables?Instead of changing the Reference table of existing variable make this variable inactive and then create a new variable that points to different Reference table. This way RITM records that were created earlier will retain their variable value.