LTT transactions are subject to revision for various reasons, for example following a review into their accuracy, or the granting of higher rates refunds.
Gall trafodiadau’r Dreth Trafodiadau Tir gael eu diwygio am amryw o resymau, er enghraifft yn dilyn adolygiad i'w cywirdeb, neu roi ad-daliadau cyfraddau uwch.