Incorrect expense billed

User allocated an expense to the wrong project phase and billed it; so needs to credit one phase for the amount and re-bill the amount to another phase. What's the best way to handle this?

If an actual expense entry was charged (i.e., both cost and billed values) to the project, it's probably best to enter a negative expense to the wrong phase and an equal, positive entry to the correct phase. You might want to add a description or memo for these entries to note why they are being made. You can pull these entries to the next invoice to correct the billing and update your client.