To access Maxit, click on Manage Accounts in the lower right hand corner of the Account screen. On the new window on the top of the screen click the link for Maxit Tax Calc.
Once in Maxit, from the Incoming Positions tab you will see an Incomplete Positions option like the one below; click on Incomplete Positions.
From here, you will click Edit on the far right of the position you are updating:
The information you will need to update in Maxit is the acquisition date(s), the quantity and total cost.