Do keep in mind that a visit visa for Luxembourg can only be extended if you have a very strong reason for asking for an extension.
The only acceptable reasons for seeking extension of Schengen short stay visa are –
- Force majeure
- Important personal reasons
- Late entry
- Humanitarian reasons
Short-stay Schengen visa extensions are allowed by the legislation of the European Parliament and of the Council (E. However, if you do not have a good reason to apply, you would have very little chance of getting an extension.
If you would like to extend your visa and remain in the Schengen Zone for a longer period of time, you can start planning your application, which varies from the standard Schengen visa application. The very first thing you have to do is decide the reason why you want to apply for a renewal of the Schengen visa. Then you can move to the other steps after finding that out.