How Do You Upgrade Mipha's Grace?

Mipha's Grace is upgraded to Mipha's Grace + after completing the quest "EX Champion Mipha's Song" as part of The Champions' Ballad DLC. The cooldown is reduced to 8 minutes.

Can you use Mipha's grace more than once?

Mipha's Grace can only be used once before recharging and cannot be used again for 24 real-time minutes. While in Hyrule Castle, Mipha's Grace instead takes eight minutes to recharge.

How do I get Miphas Grace back?

When your hearts run out, you'll automatically be resurrected with full health plus temporary bonus hearts. Following use, it needs 24 minutes (or one in-game day) to recharge and you will hear the following announcement when it is ready: "Mipha's Grace is now ready."