READ THE EXAMPLE SECTION FOR A BETTER EXPLANATION
Add a feature for normalizing units (or a different name) that you have spent rerolls on already, basically a refund mechanic. To make it balanced, instead of refunding the full amount spent, players could receive 1/4th the amount spent on that unit.
For example, when rolling for monarch on my aizen, I decided to roll on a duplicate after getting ethereal and spent around 100-120 rerolls on the dupe. So if I were to refund my dupe aizen, then I would get 50-60 rerolls in return. It could either be a monthly event where players are allowed to refund 1-3 units, a ticket which can be given through a code for milestones met or every .0 update. When a unit is refunded, the refunded unit's mythic trait pity's will be reset to 0 to avoid any way to exploit this feature. If a unit is refunded, you will have to wait until the next update to roll on it again.
It would be a nice feature to have in the game for extra rrs, especially if we don't use the unit being refunded anymore, and the ways listed would leave both players and developers satisfied


