Hi there Rebekah,
Welcome to planDisney and thank you so much for your question! This sure does sound like a conundrum - I'm hoping I can help you get to the bottom of it so you can get back to planning your next trip to the Happiest Place on Earth.
To start, we here at planDisney are Guests just like you, so I don't have access to any of the back-end systems that Disney Cast Members can use to see the specific details of your situation. Ultimately, it might be helpful to
call a Cast Member at the Tickets line to help figure out exactly what is going on here. However, I certainly have some ideas and troubleshooting tips to offer in the meantime!
First, this will largely depend on the type of theme park tickets that you have. Currently, I see the same thing that you are seeing on both the
multi-day ticket reservation calendar and the
1-day ticket reservation calendar - it does look like February 18 has reservations available for both parks.
Therefore, if you have multi-day tickets then it definitely sounds like you would want to get some more information from a Cast Member at the Tickets line to figure out how to proceed.
However, if you have 1-day tickets, while there are reservations available on February 18,
the 1-day tickets are on a tier-based system from 0-6 that determines the dates that the ticket is eligible to be used on (regardless of reservation availability). The higher the tier number, the more days that the ticket is eligible to be used and the more expensive the ticket.
For February 18, only tier 6 tickets can be used, so I'm wondering if these 4 other tickets that you're trying to make reservations for might be lower-tier tickets (Tiers 0-5)? You should be able to see this on the tickets themselves or the confirmation email the purchaser received after buying them.
If that ends up being the case, then a Cast Member at the Tickets line can help you determine if these tickets are upgrade-eligible so you can then make the reservations for your planned February 18 visit.
Thanks again Rebekah! I hope you and your group have a fantastic time visiting the Happiest Place on Earth.
Have a Magical Day,
Greg