Import Task ID changes

Summary:

How to indicate on an import file that the Task ID is changing?

Content (please ensure you mask any confidential information):

A few months into using FCCS Task Manager, we want to change the Task ID numbering structure in the template, assigning new IDs to existing tasks. I want to import this (so I don't have to manually change 1000 tasks), but Task ID is the key identifying field, so how do I indicate the new ID in the import file? In EDMCS, the column is called "New Name" in the import file - is there an equivalent for FCCS Task Manager? I need one column with the original ID and another column with the new ID that will replace the