To prevent other users from changing the control numbers of some or all of the parts in the model, use the Lock/unlock control numbers command. Later on, if the control numbers need to be changed, you can use the same command for unlocking the numbers.
On the Drawings & reports tab, click Numbering settings > Lock/unlock control numbers to open the Lock/Unlock control numbers dialog box.
Define which parts’ control numbers to lockto prevent unwanted action in a model or a drawing
It is possible to lock model objects, reference models, and drawings, for example.
To lock or unlock the control numbers of all parts, do not select any parts in the model.
To lock or unlock the control numbers of specific parts only, select the parts in the model.