You use your fingers to take down the old flag and install a new one. Flags get old, just like computers and furniture and people. So when one gets too old, you have to get on up there and install a new one in its place.
You've decided to install a suit (す) where the old flag used to be. I mean, a suit is probably more durable than a flag, am I right? This way you won't have to install flags as often.