Sequentially change a attribute in block

[lee.johnson]

Hello,
I have a project that contains a lot of callout blocks for heat pumps.
The attributes of the callout AHU type on top and number on bottom.
Instead of do each one manually, is there a way to change the bottom number sequentially by order block selection?

[BIG-AL]

This is a very simple method it uses the attribute order of creation so just enter the attribute sequence number as hinted if the bottom attribute is the second then enter 2 and the sequence number to start with.

(defun c:addnatt ( / x num att)
(setq x (- (getint "\nEnter the attribute order position eg 1 is 1st attribute") 1))
(setq num (getint "\nEnter start number"))
(while (=  (vlax-property-available-p (setq obj (vlax-ename->vla-object (car (entsel "Select Block")))) 'Hasattributes) T)
(setq att (vlax-invoke obj 'getattributes))
(vla-put-textstring (nth x att) (rtos num 2 0))
(setq num (+ num 1))
)
)
(c:addnatt)