Speaking to him normally, he will listen and you can ask for signs for confirmation. Offering something in return after help is important.
https://satanisgod.org/www.angelfire.com/empire/serpentis666/Demonic_Communication.html
You can focus on Lord Andras' sigil and respectfully ask Him for help. Be sure to give something in return such as doing an extra ritual, paying money to JOS or some other form of help.