Hey there Rhonda,
Welcome to planDisney - I'm so glad you stopped by with your question! I'm sorry to hear you weren't able to make your birthday trip due to being sick. I sure hope you're feeling better now and are looking at new dates to visit!
When it comes to 1-Day
theme park tickets, there is a tier system depending on the day. Certain days throughout the year are designated at different tier levels, typically due to expected crowd levels. The higher the tier number (from 0-6), the more days that are available to select from. However, the lower-tier tickets typically come with a lower price!
To me, the most helpful page on the entire Disneyland Resort website when it comes to 1-Day tickets is the
Help with Tickets - Frequently Asked Questions page. It does a great job explaining the 1-Day ticket tier system, outlines the blockout date ranges for each ticket tier, and also walks through how to upgrade your ticket!
If there is a specific date that works out best for you that is not available with a tier 5 ticket, your options would be to upgrade to a tier 6 ticket and pay the difference, or make a trip out of it and upgrade your 1-Day ticket to multi-day tickets, as multi-day tickets have different entitlements and validity dates. Alternatively, if your travel dates are flexible then you can always stick with the tier 5 ticket option and select a different date.
If you end up wanting to discuss upgrade options, I'd recommend
calling one of the wonderful Cast Members at the Tickets line to learn more.
Thanks again for your question, Rhonda! Make sure to grab your
complimentary Birthday Button when you do visit - and have a great trip!
Have a Magical Day,
Greg