How to change entered creds?

I am using JCL Check extension first time, and it asked me to input my user and password but I got confused as I expected it to just use the Zowe credentials. So for username I entered `user`. Now I realise this mistake, I want to go back and change my username, but I can't find the option to change it. I tried uninstalling and reinstalling extension. I tried deleting jclcheck from Zowe global config file, restarting VS Code and readding it back in.

And why it doesn't use Zowe credentials?

My global `zowe.config.json` file:
```json
{
"$schema": "./zowe.schema.json",
"profiles": {
...other profile types...
"jclcheck": {
"type": "jclcheck",
"properties": {
"port": 7100,
"basePath": "cajclcheck/api/v1",
"rejectUnauthorized": false
},
"secure": []
},
"base": {
"type": "base",
"properties": {
"host": "hostname",
"rejectUnauthorized": false
},
"secure": [
"user",
"password"
]
}
},
"defaults": {
"zosmf": "zosmf",
"tso": "tso",
"ssh": "ssh",
"cics": "cics",
"jclcheck": "jclcheck",
"base": "base"
},
"autoStore": true
}
```

Start by inspecting the `zowe.config.json` profile and secure-field entries described in the report, then trace how the VS Code extension obtains and stores JCL Check credentials. Done means identifying a supported way to change the username and clarifying whether the extension should use the Zowe base profile credentials.

Written by the indexing model from the issue text.