The specified database instance is currently in storage-full state. Please allocate more storage by modifying the DB instance

Question

One of our slaveDb is showing as Storage-full state. The initial Allocated size was 466 and Db.m4.large instance ( RDS)

Steps followed to increase the allocated space < 10% of the allocated space getting the following error

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and > 10% of the allocated space getting the following error

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Can some pls help over come and suggest the way to increase the space