I've been switched from 1D to 2D when the aircraft changed to a Polaris configuration. I was less than thrilled as it seemed to me that 1D (non-Polaris) ought to have mapped to 1F (Polaris). Worst yet, the aircraft then was switched back to a non-Polaris configuration and I found myself in 2B with 1D occupied by someone else. Fortunately, 1A was unoccupied so I was able to at least change to a seat with a larger than average footwell.