https://help.tallysolutions.com/docs/te9rel60/Licensing/change_product_edition.htm

Changing Your Tally.ERP 9 Rental Edition

You can change your Tally.ERP 9 Single User rental edition to Tally.ERP 9 Multi-User, or vice versa.

To change the product edition

1.    Start Tally.ERP 9.

2.    Click F12: Configure > Licensing > Change Product Edition. A message appears, click Yes.

o     If you are a Microsoft Windows standard user, and do not have the required rights, a message appears as shown below:

Click Yes, and enter your computer administrator username and password to restart Tally.ERP 9 with administrator rights.

o     If you have Microsoft Windows administrator rights, a message appears as shown below:

Click Yes, for Tally.ERP 9 to restart with administrator rights.

3.    Press Ctrl+A in the Change Product Edition screen, to change the product edition. The product edition details are displayed in the Information Panel.

See also

Convert to regular license

Licensing - FAQ