Most shingle repair, be it asphalt, wood or slate, follows the same rules and steps; Separate and isolate the bad shingle from those close to it, take out the nails, slide out the bad shingle, and replace. Wood shingles, shakes and slate demand that you cut the nails with a hacksaw instead of removing them, and re-nail in a fairly exposed spot; but in all circumstances, you use roof cement to seal those nail heads. Even if a damaged shingle is not easily in the field, but resides instead in a peak, valley or vent, the process stays essentially the same: isolate, detach, remove, replace, reseal.
One location where additional caution must be used is at any shingle/flashing interface. For instance, a shingle along a valley cannot be nailed too close to the flashing for fear of puncturing it; use roofing cement at the flashing end, and nails at the other end. If a shingle goes under a piece of step (occasionally called lea flashing, be extra cautious not to disrupt the flashing at all. You can expand a tiny leak to a major waterfall here. Wood shingles can last between 15 and 40 years. Their durability will depend on your climate, their vulnerability to the weather, and the pitch of your roofing. As a rule, the higher a roof, the longer the materials will last because water will not pool on it and ice and snow will not gather and damage the wood. If your roofing is leaking, or you suspect you have cracked or damaged shingles due to a recent serious storm, check your roofing for curled, broken, or split shingles. Wind and rain may erode shingles resulting in lifting from the roofing. Check for affected shingles or go in the attic and search for signs of water--either dampness or stains. If only a few shingles are affected, service or replace them. If many shingles are damaged, you may require to replace the entire roof.
You have tested out the fixes on your own and after a few days you find that the shingle is still leaking. So what exactly is the next course of action? Besides calling for a kansas city roofing company, there is no other option. So just pick up the phone and call the more experienced roofer.