If you're looking to repair your pavers, the best way to do it is to remove the old mortar with an angle grinder. This will ensure that the new mortar will be “completely new” and will match the existing pavers. Once you've removed the old mortar, you can replace any broken bricks with new ones. Make sure to use the right mortar for the job, as sand should only be used for joints.
You can also use a polyvinyl sealant like Silka mortar, which is applied with a spray gun. When replacing the bricks, be sure to check that they are level with the existing ones. You can use a sledgehammer to hit the stone into place if needed. It's important to note that the color of the new mortar won't match the old one at first, but it will over time.
So don't be tempted by quick fixes - take your time and do it right!.