Why do we hoist the flag on Independence Day but 'unfurl' it on Republic Day?

While many of us are aware of the difference between Independence Day and R-Day, it is imperative to note the difference between hoisting the flag on I-Day and unfurling it on R-Day. The PM hoists the tricolour on I-Day. The day is to mark the historic event of Independence of the country from the British Rule. On R-Day, the flag is tied up on the top and is unfurled without pulling it up. This depicts that the country is already independent.