It is indeed possible to edit the title of the first post or indeed any other post in the thread.
Advertising in the forum at large is utterly forbidden and in general breaking this rule leads immediately to a Warning. However, mentioning in a thread about how to make voice files that you need some voice actors is permitted because it is directly related to the original question and is therefore on-topic. This is not an advertising thread: there is a genuine and legitimate question here and it is OK for the original poster to post anything that is on-topic to the original post.
DAN 92 is new to our forums and OFPEC at large and as yet, due to unfamiliarity, he is not making best use of the place. (You must remember that OFPEC is a very big place.) It is the job of all members of the OFPEC family to help him and other noobs to get the answers they need as quickly and easily as possible and I am delighted, 456820, that you and others are doing everything you can to help him.
@DAN 92, although this is an English language forum the majority of members are not native speakers and abbreviations like "any 1" are not helpful to your cause: they merely reduce the number of people who understand your post. We know from experience that standard English elicits a significantly better response.