Re-delegating INJ tokens means removing your delegations from one validator and delegating them to another.
Under the Wallet page, find the Delegations section. Click the Re-Delegate button found in the same row as the validator you would like to remove delegations from.
A modal will open asking you to select which validator to move your delegations to. Pick a validator and click the Re-Delegate button.
Confirm the metamask transaction to finish re-delegating your tokens with the selected validator.