You mean you want double records of nr 284 in the same table or in a new table?
If the field is not the key, you can do it either way.
If it is, you can only make a new table. This is a simple query operation. Hit file>new>query . Chose the file containing the records and enter your criteria in the fields. For instance > 234. If you aren't sure of the syntax just go to your help files.
This will make a separate table, the answer table in your private folder. (c:\corel\<rest of path to paradox>\private\answer.db).
You can close everything now and import the contents of the answer table to your existing table, with the caveat on the keyed field.