Authenticate an EWS WCF service by using OAuth and refresh access token

Question

Hello,
I am trying to call Exchange web services (EWS) end points from my WCF service using OAuth authentication.
I have registered the app on Azure portal and able to generate and authenticate it using access token.

My question is about how I can refresh the token in WCF service. It seems access token has an hour validity.

 //Code to generate access token  
// Using Microsoft.Identity.Client 4.22.0  
//Get a token with app-only auth  
var cca = ConfidentialClientApplicationBuilder  
    .Create(ConfigurationManager.AppSettings["appId"])  
    .WithClientSecret(ConfigurationManager.AppSettings["clientSecret"])  
    .WithTenantId(ConfigurationManager.AppSettings["tenantId"])  
    .Build();  
  
// The permission scope required for EWS access  
var ewsScopes = new string[] { "https://outlook.office365.com/.default" };  
  
//Make the token request  
var authResult = await cca.AcquireTokenForClient(ewsScopes).ExecuteAsync();  

Followed below link for this.
https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-authenticate-an-ews-application-by-using-oauth

Thanks