From Archon Arcana - The KeyForge Wiki

If an ability instructs you to flip a card, that card remains in the same position in the play area, and the card is placed with its opposing side face up.

Any counters and tokens remain on the card, and their effects apply immediately. Upgrades attached to cards remain attached to the card as long as it remains in play.

Cards that are flipped are not considered to have entered play or left play for the purpose of card effects. If a card that is flipped is not eligible to remain in play in its location (e.g., an action card in the battleline, or an upgrade not attached to a creature), that card is discarded (along with any upgrades attached to it). Any tokens or counters on the discarded card are moved to the common supply.

KeyForge Master Rulebook v17.3 March 2024