I have database that has multiple schemas and objects under them. I want to consolidate the objects into one schema.
I tried
ALTER SCHEMA dbo TRANSFE
According to this MSDN page your issue may be caused by a duplicate primary key name. i.e. your table_name's primary key name conflicts with a primary key name already defined within some other table in dbo.
To resolve this issue, rename the primary key for the table that you want to move. Use a name that does not appear as a primary key in the destination schema.