How do i resync a standby database with a recovery catalog?

[dbasan]

I have created three databases. Call them T1 (primary) T2 (standby) and T3. T3 has the recovery catalog. I have registered the primary with the catalog. Is it okay to register T2(standby) with the same recovery catalog? If not how do i go about resyncing the standby database with the recovery catalog? Thanks in advance;

think about resync of T1 & T2.
When your T2 is corrupted or lost permanently you can create again from T1.
If your T1 is lost you can get back from backup(RMAN). Clear with concepts!