Requirements walkthroughs tend to feel formal, and have a well-deserved reputation for not being much fun. Externally, it's just a bunch of people sitting around a table and plodding through the requirements line by line. Yet there's substantial value in a walkthrough, especially if all the right people (and only the right people) come to the table.
The details of the requirements walkthrough and approval process will vary from project to project. But they will probably always fall within the following spectrum.
Early in the project, the business stakeholders review the requirements documents and verify that they accurately reflect their needs. Later, the developers will review the requirements, solicit questions and clarifications, and acknowledge that they understand them as they go forward with solution development.
Depending on the size and scope of the project, the requirements walkthrough and approval may require several meetings, or only one. The purpose of the walkthrough is to ensure that the right requirements are handed over to those who will create the solution. That means your development team must be there, even if it's a team of one.
The quality assurance team will also have a vested interest in the walkthrough, because they must understand the requirements and have confidence that they are testable. They may also be needed to provide additional context or clarification. They may or may not be asked to approve the requirements, but it's important that they understand them.
The project manager will also have a vested interest in the walkthrough, as a chance to learn the present state of the requirements, and listen to the participants' concerns. Even if the project manager isn't required to sign off on the requirements, it's important that they be present at the walkthrough.
The business stakeholders should also attend, even if they've already formally approved the requirements. You'll probably need more than one business stakeholder to attend, because it's important for each functional business area to be represented. It's a good idea to include someone who can answer any business-related questions the developers might ask.
If you've already held a number of review meetings with the stakeholders, you may want to invite some fresh eyes, or someone who knows the whole history of the project. You'll need to include "the business" at the meeting(s) because they are the ones who will approve the handoff. Their presence will also ensure their understanding that any subsequent changes will be costlier and harder to make.
These are the people who need to attend the walkthrough. On some projects, you may also want to invite the sponsor, to keep them close to the project. Or you might want to invite another business analyst to give you feedback (although their presence is usually completely optional). Review your Stakeholder Analysis or Project Stakeholder/Influencer Assessment for other individuals who might benefit the walkthrough review.
Once you're sure that you've invited the people who need to be there, it's time to make them want to be there. To boost their enthusiasm for the walkthrough, give them plenty of time to prepare, and keep things moving during the discussion. Let them know that you value their time and you aren't going to waste it. A walkthrough may not be fun, exactly, but it is valuable.