Item matrix template changes

Hello All,

We are in E1 9.2 working with Item Matrix.  We need to expand the size of a segment from 3 to 4.  We would like to create a new table for the expanded segment.  We have a few questions:

1.  How do we replace the original segment table with the new table in the item template?

2.  Do we need to regenerate items that have been setup using that template?

3.  Are there concerns with regenerating existing items that have a 3 digit value in the new 4 digit segment?

We need to change the color from 3 to 4.  We want to keep C1 as size 3 for other items, so we would like to create a new segment that is 4.  We would then replace C1 on this template with the new segment reference.