Since Assembly Planner is a multi-user environment, it requires you to check out an entity before editing it. This prevents different users from editing the same data at the same time. This check out feature pertains to parts, bills of materials, routings, operations, activities, and resources.
If you see a lock symbol next to the ID in the search control, or in the header, it means the entity is available for checkout. No one is working on it at this time.
If you see a red caution symbol, it means the entity has been checked out to someone else.
If you don't see a symbol next to the ID, it means you have already checked out the entity.
When you check something out, the system creates a local copy for you to work with, everyone else still sees the master copy while you are working.
When you check something back in, your local copy becomes the master copy.
To see a demonstration of how to check out and check in a routing process, please watch the video.