Oracle: duplicate schema to another database
Use expdp with the flashback_scn or flashback_time parameters, along with SCHEMAS= to export the schema at a consistent point in time.

This is the same as using CONSISTENT=Y in the legacy exp utility. Examples  here.

If the data for the schema in question is in a tablespace of its own with no other objects from other schemas, you can use rman to do a tablespace point in time recovery.