Square doesn't allow any part of a transaction to be changed once the sale is complete.
That's why I export my sales to a spreadsheet so I can edit things there. Pivot tables make it easy to pull the info I need most and total up each employees commission. It's very common for people to make a mistake. I really wish we could edit some info or even add a secondary note to a sale after the fact. It isn't generally worth the effort to me to have to refund and do a new sale. Most of the time customers are gone by the time we see the mistake and I'm not calling them to ask for payment info again when they already have the product.
I utilize the "dining options" under Items -> settings -> dining options on the menu.
I set an option for each employee, and select the employee from the dining options list to credit the right person for commission.
We are a photography company and often sell each others photos. I like being able to track which employee made the sale vs. whose photos were sold for commission. So if a mistake is made on the order, I know who to ask. We also regularly have multiple photographers work on one ticket, so I can set the dining option per item to calculate their commission.
I realize this is different from your needs, as it sounds like the employee making the sale is the one getting commission regardless of what was sold, but thought it might give you another option. At least this way, they wouldn't have to log in under another person's number. However, the dining option info is really only usable by creating a custom report or exporting to a spreadsheet. It also doesn't prevent mistakes and you can edit after the sale closes. Again why I do payroll from spreadsheets, not square's reports.
