Recreating a corrupt index

I am having problems with redo logs not applying to a standby database. Getting the error 'redo is inconsistent with data block'. I traced the error to a corrupted index on the standby machine.

I tried recreating the index on the standby database, but am unable to do so. I keep getting the message 'database is read-only'. I tried making the database read/write, but each time I try to recreate

the corrupted index I keep getting the 'database is read-only' so I am not able to recreate the index. Is there a way to drop/recreate an index on a standby database?