Are these 2 people "managed" by you in
MDE? Or do they have their own accounts and you are linked? If the former, you should be fine leaving the unused tickets where they are and eventually re-assigning if need-be once you update them. However, keep track of the ticket numbers because they are likely to disappear from your view after expiring.
If either/both of these 2 individuals have their own MDE and are linked to you, you might want to ask them to re-assign the tickets back to you. You can store them in another profile, or create a dummy profile for this. The issue comes that the individual "holding" the ticket becomes the "owner" from WDW's perspective and that person would need to do the upgrade when time came to use the ticket(s) for a future visit.