There is a new action term for treaties that can be offered or demanded between cities:

RESERVES <amount> : (Between cities only) Transfer units
from your war reserves to the other
party as a one-time gift, taken when
the treaty is ratified. They will only
receive as many as they have room to
hold beneath their reserve maximum;
any remainder stays with you.

For some context behind this change: reserves could previously only change hands by marching troops into another city's barracks and disbanding there. Due to a mistake on our end, some parties were misinformed about how this worked and made plans off that bad information, which led to things playing out in a way they otherwise wouldn't have. All involved parties in the conflict were given a heads up on this change a few hours ago. There's no clean way to unpick something like this after the fact, so this is the best option we have available.

Penned by my hand on Kinsday, the 6th of Omeian, in the year 20 AC.