No matter what I try Import is always greyed out on the fields tab unless I start with New Feature class.

I al trying to get an existing table to match the schema of a diff table. I need the order to match so I can do a UNION ALL.
Because the FC has over 20 Relationships classes off of it I cannot just create a new table and move the table. Even renaming back and forth is a no go. I tried the reorder in SQL but getting weird rights errors even though I am the DBO.
Thanks