Shift your ground - Idioms by The Free Dictionary
shift your ground
shift (one's) ground
To adopt a different viewpoint or opinion. I was shocked when Liz suddenly shifted her ground and started seeing things as I did.
shift your ground say or write something that contradicts something you have previously written or said.
shift your ˈground (usually disapproving) change your opinion or position, especially during an argument or a discussion: He’s shifted his ground on many major policy issues. OPPOSITE: stand fast/firm