That depends on why and when. If you need more money in the short run (ie within two years), because you miscalculated how much you would need, or the returns are coming in more slowly than you anticipated, or something else has gone wrong, the answer is probably no. Both investing institutions and business angels are fairly hard-headed, and you are most unlikely to be able to tempt them into throwing good money after bad.
But if you need more money in the medium-term, to expand production, or move into new markets, the answer might well be yes.
