how to remove special instructions data in the sc task after state is getting completed

[raj765_32]

hi can anyone help me with scenario for 

when i submit a catalog item there are three sc tasks in where i have written a code in 2 and 3 rd sc task to display some value in special instructions field.

What happening is that after i close complete 1 st sc task, the data/value written in  2 and 3 sc task is getting displayed when 1 st sc task is closed complete. 
please help me how to fix this and where to fix this in which sc task.

below is the code :

var gr = new GlideRecord('sc_request');

gr.addQuery('sys_id', current.request);

gr.query();

if(gr.next())

{

gr.special_instructions = "1. Complete template to request EP End User Access form Blue Yonder. \n\n2. Submit request (Medium priority) via Blue Yonder portal. 

gr.update();

}

my requirment is that it should not display in 1 st sc task when the task is completed or what ever state it should display in 2 and 3 sc task only

[Vishwa Pandya19]

Hello,

Do you want to remove the value from the Special Instructions field for all Catalog Items or a certain catalog item?

[raj765_32]

only for one catalog item and i have to display value in special instructions in 2 nd and 3 rd sc task only