A padlock on a calendar event means that event belongs to another organisation, not to your account. You're seeing it because they've shared availability with you. It's view-only on purpose.
What you can and can't do with a locked event
You can see that the date is taken. The padlock tells you the artist is unavailable, which is the point — it keeps you from double-booking.
You can't open it. The event's details belong to the organisation that created it.
You can't edit, move or delete it. Only the team that owns the booking can change it.
This isn't a permissions problem on your side and it isn't a fault. No setting on your account, and no role change, will unlock it — the restriction sits with the organisation that owns the event.
If you need the details
Note the date and the artist the locked event sits against.
Contact the organisation handling that booking directly — they can share whatever detail you need, or send you the itinerary themselves.
If you're working the same date together, ask to be added to the booking on their side. Once you're on it, it stops being a locked event to you.
Good to know
Locked events work the same way in reverse. Bookings you create show as locked, view-only entries to organisations you share availability with, so your details stay yours.
If you expected to own an event and it's showing locked, it was most likely created by the other party rather than by your agency. Check who raised the original booking before assuming something changed.
Locked events still count for availability purposes, so hold dates and conflict warnings behave normally around them.