Circular reference (API refreshtoken)

[JoeVBAHelp]

Hi experts

I am having an issue with a cicular reference within Power Query when using refresh tokens

Basically, use refresh token than returns and access token which I feed into get the results.

The problem is when the refresh token is run and updates, I need to use that output next time.

But that means query (reftoken1) needs to be updated by / and feed into the Data query.

I have solved by storing a table in excel but this wont work for Power BI.

Basically what I need:

Refreshtoken1 = feeds into the data
Data = returns new refresh token
Refreshtoken2 = from Data (new token)

If refreshtoken1 <> refreshtoken2 then Refreshtoken2 else refreshtoken1

anyone have any ideas on how to fix this ( I was thinking I need to declare a variable but i don't think this is possible)

authKey = "Basic " & Binary.ToText(Text.ToBinary(access_key & ":" & secret_key),0),
 url = "https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer",
 // Uses POST method to obtain a bearer token
 GetJson = Web.Contents(url,
     [
         Headers = [#"Authorization"=authKey,
                    #"Content-Type"="application/x-www-form-urlencoded;charset=UTF-8"],
         Content = Text.ToBinary("grant_type=refresh_token&refresh_token="&refreshtoken) //this is the circular reference -refreshtoken comes from the output to this query
     ]
 ),
Res = Json.Document(GetJson)
in
    Res