When a person becomes a Muslim, should he remove his name from the voting list?

It is not necessary to remove your name from the voter's list. Voting is something that may be necessary to protect the community from harm. But if the system is an un-Islamic system, we cannot uphold what it stands for. However, if you know two candidates who are seeking election, either one of the two will be elected, one of them is an open enemy to Islam, the other one speaks nicely. What do you do here? Do you just say I leave it to Allah? If you have the vote and can bring the one who speaks nicely and is not an open enemy to Islam, then do it, use your vote. Try to elect the lesser of the two evils.

So, I would not say that you should strike your name from the list. Where your vote can make a difference, use your vote there. But, if both are the open enemy, no one is better than the other, and your vote cannot make any difference, then don't waste your time in going to cast your vote.

Shaykh Muhammad ibn ‘Uthaymeen (may Allaah have mercy on him) was asked about the ruling on elections, and he replied: "I think that elections are obligatory; we should appoint the one who we think is good, because if the good people abstain, who will take their place? Evil people will take their place, or neutral people in whom there is neither good nor evil, but they follow everyone who makes noise. So we have no choice but to choose those who we think are fit. If someone were to say: We chose someone but most of the parliaments are not like that, We say: It does not matter. If Allaah blesses this one person and enables him to speak the truth in this parliament, he will undoubtedly have an effect. But what we need is to be sincere towards Allaah and the problem is that we rely too much on physical means and we do not listen to what Allaah says. So nominate the one who you think is good, and put your trust in Allaah." [1]

Reference:

[1] From Liqaa’aat al-Baab al-Maftooh, no. 210; http://www.ibnothaimeen.com/all/sound/article_16230.shtml