If you have an Uncashed Check to Replace, the "offset deposit" is to a Liability account, so that you can pay out that liability on a new (replacement) check.
If you have an Uncashed Check that also is not being replaced, your offset deposit is going to be where you list what you want to reverse, such as Office Supplies expense wasn't incurred, after all.
In both examples, the Uncashed Check and that offsetting Deposit are both Marked as cleared in the next reconciliation. They net to 0, so no impact on that reconciliation ending balance.
