如果没有刷新token，则可以使用客户端凭证流来获取新的访问token。以下是使用Python的示例代码：

import requests
import json

tenant_id = "your_tenant_id"
client_id = "your_client_id"
client_secret = "your_client_secret"
resource = "https://graph.microsoft.com/"

# Get the access token
auth_url = "https://login.microsoftonline.com/{}/oauth2/token".format(tenant_id)
auth_data = {
    "grant_type": "client_credentials",
    "client_id": client_id,
    "client_secret": client_secret,
    "resource": resource
}
response = requests.post(auth_url, data=auth_data)

if response.status_code == 200:
    # Parse the response to get the access token
    access_token = json.loads(response.text)["access_token"]
    # Now you can use the access token to make API calls
    # For example, to get user information from the Microsoft Graph API
    user_url = "https://graph.microsoft.com/v1.0/users"
    headers = {
        "Authorization": "Bearer " + access_token,
    }
    response = requests.get(user_url, headers=headers)
    if response.status_code == 200:
        print(response.text)
    else:
        print("Error getting user information: " + response.text)
else:
    print("Error authenticating client: " + response.text)

此示例使用客户端凭证流来获取访问token，并使用访问token从Microsoft Graph API中获取用户信息。这是一种在没有刷新token的情况下获取新的访问token的方法。