If its different from the old s19 units then he can just point the blower or hotair on the front of the heatsink near on that chip just to give a bit heat because some parts is not fully soldered there some parts have cold solder joint. So giving them a heat can melt it and gives more contact from chips to the board.
You need to understand that solder issues and heatsink issues are completely different, and they result in different logs regardless of the miner model, if there is an issue with the solder whereby the chip is not in contact with the hashboard, it will cause a board failure such as missing asics or no asics at all.
On the other hand, a loose heatsink will not display any error, in fact, the miner will read all Asics and will run just fine for a few seconds and then stop after throwing a temp error, many people (myself included) thought the issue with the 17 series was about heatsinks losing contact to the chip, but no, it turns out that it's the actual chip, you can confirm that yourself by taking out a few heatsinks and the miner will still get full asic count, mine for a while and those chips without heatsink will without a doubt pass the max temp in a few seconds and will display "over-temp on chain x" power off.