Am I correct in thinking the following rules apply when you have to move your bid to a new tile because you have been outbid?
1. You can move to any tile that has no bid as long as your (unchanged) bid is greater than the tile's minimum bid.
2. You can move to any tile that another player has bid on as long as your (unchanged) bid is greater than the other player's bid. That player must then immediately move his bid to another tile (or take it back).
You are right in both points.
Additional: If you are not able to get another tile or if you don't want another tile, you get 1 silver coin from the bank.