SharePoint 2010 had an option “Log in as another user.” In 2013, this option (default) is not present. With a little modification you can retrieve this option.
Navigate to the “Login as a different user page”
A quick way to go to the page is to adjust the URL. Go to the following URL.
! Please note the capital C in Connection
After the pags is loaded the familiar pop up appears to you to fill in your username and password. After submitting you wil be returned to the previous page.
A more permanent solution is to cutomize the welcome page. I found this i a post of Gokan Ozcifci. This post explains how to add the an element in Welcome.ascx.
<SharePoint:MenuItemTemplate runat="server" ID="ID_LoginAsDifferentUser" Text="<%$Resources:wss,personalactions_loginasdifferentuser%>" Description="<%$Resources:wss,personalactions_loginasdifferentuserdescription%>" MenuGroupId="100" Sequence="100" UseShortId="true" />
Wictor Wilén has made a WSP project to change welcome control.
Bookmarklet to Sign in as a Different User