Change the value of variable at runtime

Please help me to understand what you want to achieve. What do you mean with "tag" and "document". Please elaborate.

while generating document tags are replaced by the values 

In Single document  if single tag is placed more than one time then it always replaced with a single value  suppose ##Name## placed 4 times in a single document the all the tags replace with the same value .

example:-

##Name## : Richa

##Name## : Richa

##Name## : Richa

my requirement is when i place single tag more than one time in a document then it replace with the different values

example:-

##Name## : A

##Name## : B

##Name## : C

while generating document tags are replaced by the values 

In Single document  if single tag is placed more than one time then it always replaced with a single value  suppose ##Name## placed 4 times in a single document the all the tags replace with the same value .

example:-

##Name## : Richa

##Name## : Richa

##Name## : Richa

my requirement is when i place single tag more than one time in a document then it replace with the different values

example:-

##Name## : A

##Name## : B

##Name## : C

OK, got it. This Smart Service does not support that. For this to work, tags must be static and unique.

Any other smart service , which support this approach?

Depending on what you want to achieve, this one might be an option.

community.appian.com/.../advanced-document-templating

I was suggesting to try this plugIn, but i don't have specific experience with this one. But worth a shot. 
@Richa you can share your epxerience once you found a solution :) 

Document Template would be static. So it would have a fixed number of ##Names## tag in your case.

Why don't you name them as ##Name1##, ##Name2##, ##Name3##, ##Name4## ?

or anything to make them unique and you can map it as usual.

If you are using dynamic templates within the node, even then the keys should same, and if you are trying to achieve this to code the values easily, you may try to get a list of names and index it to the keys

Eg:

you have your data as say in a pv!docData: 
{

name: {    "Richa S", "R Sharma", "Richa Sharma", "Sharma Richa" }

}

then in your node, you can map the keys as:

Name1: index(pv!docData, "name", 1)

Name2: index(pv!docData, "name", 2)

Name3: index(pv!docData, "name", 3)

Name4: index(pv!docData, "name", 4)

Hope this helps ! 

Or, can you explain your use case a little more, why do you need same tag to iterate on a list ?

this is what client want

let suppose we have 3 product  A) TV, B) PHONE ,C) Washing MACHINE

in document page A) product is not available then i want other product {B) To A) }to auto shift 

Perhaps thinking about it a little differently...could you not have ONE tag that will hold ALL of the details formatted as you describe and you can construct that in a rule before passing it to the tag? We do this with emails sometimes, where it's just easier to have the content constructed entirely in a rule, and then dump the entire content to the email. So you could have a tag named ##CONTENT## and this is replace by the formatted value from a single rule that covers everything you need it to contain.

I agree with Stewart here.

It's much easier to have it as ONE tag at least for this part of your document, and prepare this in a rule where you could play around easily with what data to put when one product is not available

i already made rule 

a!localVariables(
local!data:{"name","name","name"},
local!test:count({"name","name","name"}),
a!forEach(
items:local!data,
expression:if(
fv!index<=local!test,char(sum(64,fv!index)),
char(sum(64,fv!item.[fv!index]))
)
),

)

but while placing tag value in the document  how to identify the no of count of that tag in a document