You can't as it is advertised at the tibia website. Other features of being premium account are:
No you can’t train offline as a free account but you can buy training weapons in store or at any magical shop ;p even as free account and train in adventurers guild dummy or see if there is any together with the training statues at your city...
(it says on tibia site what you can get as premmium and free accounts here: https://www.tibia.com/abouttibia/?subtopic=premiumfeatures )
Outstanding Contribution contestSeptember 14, 2020
Hints for posts that received a down-voteAugust 15, 2020
I've received a down-vote - how can I fix it?August 14, 2020
Interview with Benjamin Zuckerer - managing director at CipSoftMay 07, 2020