Getting InvalidOperationException on Table.Attch(TEntity,TEntity) method

[tnk0205]

I have a Table which have 14 key-value pair. I want to update value of a particular key. I am doing Table.Attach(entity,original). Where entity and original are both type of TEntity. I am getting "Invalid Operation Exception" here with message "Cannot attach an entity with the key that already exists.". Can you help me on this?

[MariiaI]

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