On SaaS applications (cloud)

There is a shortcut button in top right that would open available companies and environments.
By clicking it, it opens list of companies from which we can select different one and select “Switch”.

Old systems or if button not visible

Open “My Settings” and Click “Company” in the main menu and the list will all companies will appear on the screen. Choose the company from drop-down list you want to open and click OK.