Unable to activate Multilevel categorisation schema

Dear All,

We have a schema created long back “Z_Schema” and is working fine, linked with service request. But now we have a requirement to create all together new schema for a different txn type.

Old Schema:

Created on and Valid from 03.03.2014

New Schema ‘”Y_Schema” is created on 20.12.2014 and status is active.

So how to make Y_Schema Active and not the other one....

Thank you.