If you didn't copy rman backup pieces between the hosts you could use active database duplication.
Below you can see an example script.
# This script will clone a target database
# a password file and tns needs to be configured on the target side and source side
# passwords need to be the same
spool log to '/tmp/duplicate_scanB.txt'
# Connect to the TARGET database
connect target sys/**@scanA
# Connect to the AUXILIARY database as set by ORACLE_SID
connect auxiliary sys/**@scanB
CONFIGURE DEVICE TYPE disk PARALLELISM 3;
duplicate database to scanB
from active database