You mean like "reserve" the record, making changes impossible for others?
If so, then what you'd have to do is have a field for it in the table and when the user wants to reserve or lock the record, write to that field. Then, in your BeforeUpdate for the form you can examine the field and if it's reserved, Cancel = True. You could also set AllowEdits to False if the field indicates the record is reserved in your On Current for the form.
Hopefully that will set you in the right direction
