Monarch Money connects differently to Capital One, Charles Schwab, and Wells Fargo accounts. If you have added your account in a way differently than described below, your first step is to disconnect your existing account.
Next, add a synced account for your account. Instead of using the "Search 10,000 + other institutions" button, click the buttons displayed for Capital One or Charles Schwab.
This will take you to the menu shown below. Click "Next".
Please note that by removing your old account you will lose any existing transaction history associated with the old account, and when you add the account a new transaction history will load.
When importing a new account it is impossible to know how comprehensive your transaction history will be once imported. If you choose to leave the old account while also adding a new one (not recommended), account balances and transactions will be duplicated and incorrect.