How to update transactions in Google analytics?

I am using the enhanced ecommerce plugin for Google Analytics.

I am using analytics.js to send transactions to Google Analytics.

After completing the transaction means confirming order,user can edit the order and add/remove items.

So we manage this thing in Google analytics?

You have a few options in GA:

• collecting refunds events attached to a transaction, where a full or partial refund can happen. Refunds are different from Revenue: Revenue will remain unchanged, but you get Refunds next to it.
• revert completely a transaction by applying a new one with negative values, but I would recommend to do it only on the same day as the original transaction

Refunds can be performed through

• Measurement Protocol calls https://developers.google.com/analytics/devguides/collection/protocol/v1/devguide#measuring-refunds (including in Javascript)
• Data Import https://support.google.com/analytics/answer/6066862?hl=en either manually of through the API

Reverting a transaction on the same day can be done through Measurement Protocol calls https://support.google.com/analytics/answer/1037443?hl=en

If you don't revert on the same day, and look at a date range that includes the original transaction but not the negative transaction that reverse it, you will still see the original transaction. If you extract daily revenue, same effect: you'll get unaffected revenue on original day AND minored revenue on the day you reverted the transaction. This is not optimal.

But keep in mind that GA isn't your accounting system. And people have the right to block GA tracking.