Tutorial Video. Step by step below;

1

First Step

Login to your Wepwawet Control Panel
2

Second Step

Select your Server
3

Third Step

Make sure to Turn OFF the Server
4

Fourth Step

Under the General Section, Click the Files tab
5

Fifth Step

Select all the files by clicking the Checkbox near /home/container/ and click the Delete button.
6

Sixth Step

Under the Minecraft Section, Go to the Version tab and search for the version you want to install.
7

Seventh Step

Click on the Install button
8

Eighth Step

Start your Server afterward.
9

Ninth Step

Accept the EULA by pressing the I Accept button
There you go! You just reset your entire server to your preferred server software!