The Numbering - lines and objects command allows user to perform various operations on numbers. One of them is Renumbering. The operation is possible when there are already numbered objects in the current drawing.
Renumbering and formatting dialog box
The Renumbering and formatting dialog box displays all the strings and numbers that exist in the drawing. User can perform the following operations on these numbers:
Shift numbers in chain - this option allows user to move numbers from a selected sequence up (+) or down (-) by a specified amount, or move numbers to a specified starting number (=). During renumbering, it is possible to remove gaps in numbering. Example: user already has numbered objects and wants to “prepare” space for 2 additional numbers between numbers 5 and 6. This means that they must move all numbers from number 6 up by two positions.
Remove gaps in numbering - this option allows user to organize the numbering by detecting and removing gaps in the numbering that occurred, e.g. after deleting some numbered elements.
Remove whole numbering chain - this option allows user to remove all numbers from a given number sequence.
Renumber geometrically - this option allows user to renumber objects according to their position in the drawing, e.g. from the upper-left to the lower-right corner (with "searching" for elements in rows or columns).
Change format - allows user to change the numbering format, i.e. specify the number of "leading zeros" in numbers.
6 Procedures
Renumber
1.
Run the Numbering - lines and objects 
command.
2. Select an object that has a number. A dialog box will open.
3. Select the Renumber button to start the renumbering mode.
4. Select the Renumber option in the dialog box. If necessary, select the items to be renumbered from the selection list.
5. Click OK.