Reindex throws away the block chain index and chain state (the database of all unspent transaction outputs), and rebuilds those from scratch. It is exactly like downloading the block chain again from peers, except the blocks already on disk are used.
1) Restart Agama, Select dropdown click on "custom" Instead native mode
2) Click on Activate coin
3) Select "Komodo coin" on dropdown and select "Daemon Param: Reindexing blocks from disk"
4) Click on Activate coin, This will take some time to reindex database folder in Komodo directory.