How do you get the team name that an agent is assigned to?

To get the Team name of the team the agent is part of, you can use the User - GET User REST API. 

<User>
    <uri>/finesse/api/User/1234</uri>
    <roles>
        <role>Agent</role>
        <role>Supervisor</role>
    </roles>
    <loginId>1234</loginId>
    <loginName>csmith</loginName>
    <state>NOT_READY</state>
    <stateChangeTime>2012-03-01T17:58:21.234Z</stateChangeTime>
    <pendingState></pendingState>
    <reasonCodeId>16</reasonCodeId>
    <ReasonCode>
        <category>NOT_READY</category>
        <uri>/finesse/api/ReasonCode/16</uri>
        <code>10</code>
        <label>Team Meeting</label>
        <forAll>true</forAll>
        <id16</id>
    </ReasonCode>
    <settings>
        <wrapUpOnIncoming>OPTIONAL</wrapUpOnIncoming>
    </settings>
    <extension>1001001</extension>
    <mobileAgent>
        <mode>CALL_BY_CALL</mode>
        <dialNumber>4085551234</dialNumber>
    </mobileAgent>
    <firstName>Chris</firstName>
    <lastName>Smith</lastName>
    <teamId>500</teamId>
    <teamName>Sales</teamName>
    <dialogs>/finesse/api/User/1234/Dialogs</dialogs>
    <teams>
        <Team>
            <uri>/finesse/api/Team/2001</uri>
            <id>2001</id>
            <name>First Line Support</name>
        </Team>
        <Team>
            <uri>/finesse/api/Team/2002</uri>
            <id>2002</id>
            <name>Second Line Support</name>
        </Team>
        <Team>
            <uri>/finesse/api/Team/2003</uri>
            <id>2003</id>
            <name>Third Line Support</name>
        </Team>
... other teams ...
    </teams>
</User>