Multi-class characters obtain all of the weapon proficiencies for all of their classes – both the starting proficiencies and the proficiencies gained by leveling up.

Dual-class characters gain all the starter weapon proficiencies for their new class, and then gain weapon proficiencies at the regular rate for that class.

There are no core rules for retraining weapon proficiencies.

As a rules extension, a weapon proficiency can be exchanged for another in 1 month at the cost of a cumulative 250 gp times the highest class level of the level of the character (1st = 250, 2nd = 750, 3rd = 1500, 4th = 2500, etc.).^Ex As with regular training, the character cannot perform any other activity during this time; if they do, all progress and expense is lost.