How to modifiy settings for an existing index?

Hi,

I try to modify settings for an existing index.
So I have closed the index and executed the following command :
curl -X PUT 'localhost:9200/myIndex/' -d '
{
"settings" : {
"index" : {
"number_of_shards" : 1,
"number_of_replicas" : 0,
"analysis" : {
"analyzer" : {
"ta" : {
"type" : "custom",
"tokenizer" : "standard",
"filter" : [ "standard", "word_delimiter", "lowercase", "synonym", "stop", "kstem" ]
}
},
"filter" : {
"synonym" : {
"type" : "synonym",
"synonyms_path" : "analysis/synonym.txt"
}
}
}
}
}
}'

But I have the error "IndexAlreadyExistsException".

So how to do ?

Best regards,

Rudy.