Oracle SQL primary key stuck

I am having a curious problem. I am making copies of existing tables and adding sections to them.

The process looks like this:

• Rename the current constraints (cannot remove them without dropping the table because I will need the data later)

• Create a new partitioned table that will structurally copy the current one. so I have MYTABLE
  
  (original) and PART_TABLE
  
  (new partitioned) including FKs

• Copy data with offer INSERT INTO SELECT
  
  

• Change table with indices and PK

• Rename the tables so I end up with MYTABLE
  
  (new section) and TRASH_TABLE
  
  (original)

In step 4, unfortunately, I got the error

ALTER TABLE MYTABLE ADD CONSTRAINT "PK_MYTABLE"
    PRIMARY KEY ("MY_ID", "SEQUENCE")
    USING INDEX LOCAL TABLESPACE INDEXSPACE;

      

        
        
        
      

    

SQL error: ORA-00955: "name is already in use by an existing object"

Now I logically assumed that I just forgot to rename the PK, so I check TRASH_TABLE

, but I see the correctly renamed PK there.

I also ran

SELECT *
FROM ALL_CONSTRAINTS
WHERE CONSTRAINT_NAME LIKE 'PK_MYTABLE'

      

        
        
        
      

    

and it returned 0 results. It's the same with the table USER_CONSTRAINTS

.

Renamed PCs are displayed correctly.

Another thing I noticed is that only PCs are locked this way. Adding FK or UNIQUE constraints works fine.