How to Change workgroup name on technicolor TG582n

[#1]

Hello All,
I need to change the workgroup name in the Plusnet router (TG582n)    Software Release: 8.4.4.J.
I have been to toolbox but there is no option for content sharing showing, only 7 icons not 8.
Help desk has advised asking the forum how to get there,as someone will know.
Thank you in advance.

[#2]

Unless I am missing something - or I don't know what I am talking about  - workgroups are set up and controlled within Windows not the router as the router neither knows nor cares what the workgroup is

[#3]

The telnet command to change the workgroup name should be:
contentsharing cifs config workgroup=WORKGROUP
saveall
Although if it's not in the web config I would have thought that's because the router doesn't have a USB port, so perhaps the content sharing services should be disabled instead:
contentsharing cifs config state=disabled
contentsharing upnpav config state=disabled
saveall

[#4]

'Tis when I check with view network that I find that the modem / switch is on a different workgroup to the rest of the LAN.
I wanted to rename so all were the same.
(I didn't want to rename them all to  WORKGROUP)
Support gave a way to do it but unfortunately content sharing is no longer an option in toolbox, so another way is needed.
You guys were suggested.
I have not used telnet commands before, what is the step by step instructions please.
The Plusnet router has been changed to suit Plusnet ease, this is an option on the TG582n that has been removed by Plusnet.

[#5]

See here for telnet instructions: http://npr.me.uk/telnet.html#telnet
I think it was removed from the web interface because the USB port was removed, without a USB port the router doesn't have any content to share. But the content sharing services weren't actually turned off in the 8.4.4.J firmware, merely removed from the web interface.

[#6]

Thank you ejs,
I followed your instructions and it worked, using your commands.
Now the router is on the same workgroup as the rest of the LAN.
Thank you