Each customer in Workforce can have one main site, also called the default site. It's shown under Main Site Details on the customer's page. You can change it to any other site that belongs to the same customer.
Before you start
The site you want has to be linked to the customer already. If it isn't, add it to the customer first, then come back to these steps.
You need permission to edit customers. If you don't see the Edit Customer button, ask your Workforce administrator.
Steps
Go to Customers and open the customer.
Click Edit Customer.
Pick the new main site. How you do this depends on which screen you have:
If you see a list of sites with "Set Default" links: the current main site has a red Default label. Click Set Default next to the site you want. This saves straight away.
If you see a "Default site" dropdown under "Sites and notes": choose the site from the dropdown, then click Save changes.
Go back to the customer's page and check that Main Site Details now shows the new site.
Good to know
When you add a customer's first site, it becomes their main site automatically.
If the main site is deleted, the customer won't have a main site until you pick a new one. The customer's page then shows a link: Please click here to set your default site.
If you see the message "Please use [system name] to edit customers", your customers are managed in another system that's linked to Workforce. Change the main site in that system instead.