@Ellinastathi_twitter You should be able to set that on your web host, or you could configure your .htaccess to redirect. The web host configuration is probably easiest to set up properly.
For the record, I would do it a little differently... I'd actually set up a subdomain on the web host pointing to a different folder, get everything working, then switch the path the root domain is pointing to.
Also - when you change the path, you will need to remember to update the Permalinks page. Saving the settings will fix any broken links pointing to the temporary space (as long as you haven't hard-coded them.).
I'll have to talk to my hosting provider to translate that for me, but it sounds logical. I'm totally willing to try this. Permalinks.. I'm going to copy/paste your comments and research how to implement.