How to refresh OAuth token and switch user in Spring Security 2.2.3?

Question

I need similar functionality as Google/YouTube that lets you switch user account that belongs also to you.

There is authentication server based on Spring Security.

How it works now:

1. User enters login and password in web application
2. Web application sends his credentials to authentication server and receives JWT token

POST /token?username=user&password=pass&grant_type=password&scope=read

3. When we have JWT token, it's included as Authorization Bearer header in every HTTP request
4. User wants to switch account without re-entering login and password - we need to get other account's JWT

When you add your own endpoint, Principal is null:

@PostMapping("/switch")
public void switchUser(Principal principal) {
    System.out.println(principal);
}

If Principal was set (based on existing JWT token sent in Authorization Bearer header), I could manually get user from database, verify if requested account belongs to user and generate JWT token.

There is also no way to refresh existing token - no refresh token comes in response.

This is configuration below:

@Configuration
@EnableAuthorizationServer
@RequiredArgsConstructor
public class AuthServerConfig extends AuthorizationServerConfigurerAdapter {

  private final AuthenticationManager authenticationManager;

  @Override
  public void configure(AuthorizationServerEndpointsConfigurer endpoints) {
    endpoints.authenticationManager(authenticationManager)
      .tokenStore(tokenStore())
      .accessTokenConverter(converter());
  }

  @Override
  public void configure(ClientDetailsServiceConfigurer clients) throws Exception {
    clients.inMemory()
      .withClient("client_name")
      .secret("{noop}client_secret_phrase")
      .authorizedGrantTypes("client_password")
      .scopes("read");
  }

  @Bean
  public TokenStore tokenStore() {
    return new JwtTokenStore(converter()); // converter used to add more fields
  }

  @Bean
  public JwtAccessTokenConverter converter() {
    JwtAccessTokenConverter converter = new JwtAccessTokenConverter() {
      @Override
      public OAuth2AccessToken enhance(OAuth2AccessToken accessToken, OAuth2Authentication authentication) {
        var token = (DefaultOAuth2AccessToken) super.enhance(accessToken, authentication);
        /* ....... adding more fields here ........ */
        token.setAdditionalInformation(info);
        return token;
      }
    };
    /* ...... loading key store here ...... */
    return converter;
  }
}

Does Spring support any functionality of switching user accounts based on JWT token? How to read existing JWT token and get user credentials based on the JWT? Do I need to write additional filter or to configure extra Spring Security features?

TL;DR: Having existing JWT token, I need to generate JWT for another account that belongs to user.