A HOLD signal is a warning signal. If you own the stock don't sell it yet, If you don't own it don't buy it yet. If you just sold the stock and now there is a hold signal this is telling you to add it to your watch list for later, or move along to another stock trade.
A stock with a sell signal can recover. It will move back to a HOLD first, then a buy.
If the stock does not recover it may move to a new uptrend (BUY) or it may roll back over and prove it is a new downtrend.