When another user is editing a record that you're viewing, a popup will display and give you three options; Ignore Changes, View Changes, or Reload Page.
If you are confident that your edits are accurate and up-to-date, you have the option to ignore the changes which were made by the other user accessing the record. Clicking this button will overwrite their edits with yours when you click "Save Record".
Clicking "View Changes" will allow you to compare the other user's data entry to yours side-by-side.
Clicking "Reload Page" will refresh the record, the fields will then contain the edits that were made when the other user clicked "Save Record"