I checked Apple's current support instructions, and the button is conditional. “Share Age Range Again” may appear only if the account has moved into a new age range or previously denied sharing. If the app already shows Shared and neither condition applies, the app detail page may have nothing to tap; there isn't necessarily a per-app unshare control there.
For a child account, the family organizer or parent can manage the sharing preference from Family settings. If you're trying to repeat the consent prompt during development, Apple's WWDC demo describes Share Age Range Again as the way to clear the cached response, but the control may not be available for every existing Shared entry. What iOS version is this device on, and is it an adult or child Apple Account? Those details matter here.
Apple's support article says the button may be available after an age-range change or a prior denial; it doesn't say every Shared entry can be reset manually.
Topic:
Developer Tools & Services
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General
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