In version 11 it is possible to propose a change to a CI linked to a Ticket without actually updating the CI record. Once the Ticket gets to a certain state or is approved, the proposed changes will automatically update the CI record. There is no functionality for this in v12 currently.
Workaround: Add fields with the same name as CI fields to your Ticket form. Allow people to propose new values for them and then configure a Rule to update the linked CI at the desired time. This will only work when a single CI at a time is linked to a Ticket.