Is there any way to change the topic of my proposal, for example from Technology to Life, or i should to delete it and create it again?
As a proposal owner, you can change the title and description of the proposal, but not the category (i.e. a change to Business, Culture, Life, etc).
For those cases, you can either
flag the proposal or request the change here (in discussion) and I can change it.
But just to note for anyone else looking on — not all flags and requests for changes are acted upon immediately. There typically is not a large community here to indicate if we have a convincing consensus that such changes are productive; so I often let the proposal continue as-is until which time the need is obvious, or the proposal reaches the "final review" where the proposal is finalized (and often clarified) in preparation for the upcoming launch.