The following will reduce potential outage duration by making these changes prior to deleting and re-adding a resource record in a live domain.
1. Login at https://portal.ultradns.com
2. Click Domains
3. Click domain that contains the resource record you plan to edit
4. Click Properties
5. Click Edit next to SOA Record
6. Change Min Cache to a low value, such as 300
7. Click Save
Lowering the SOA's Min Cache will likely increase your query volume.
You can revert the changes after you've made any planned deletions and re-additions.