If you have a team approval step in your approval workflows, you have the option to allow all team members OR just any one team member to approve to continue onto the next step in the workflow.
If you select the OR option for your approval step, the "Claim Approval" function will become active in the approval grid for those approvers.
When one team member claims the approval for that item, they are assuming responsibility for approval. The other approvers will be able to see the pending PO/invoice/payment, but will no longer have the ability to approve it.
The benefit of this feature is to reduce the number of reminder emails team approvers receive. Additionally, it allows team approvers to focus on specific accounts and vendors within a group.