Definitely, at least 2 tables. In the Accounts table, you need a field to have a field to hold the Unique ID of the Sales Rep. And you relationship will use the Unique ID (an auto-enter serial number) from the Sales Rep table and that foreign key in the Accounts table.
Can any of the accounts have more than one sales rep covering it?
Can a sales rep be assigned to an existing account when another sales rep quits? Do you want to report the aged commissions against the original sales rep?
There will only be 1 saleman per account, and if a sales person leaves, the account won't be reassigned but just become a "house account". Essentially it will be orphaned and assigned back to the company internally. I won't really need to track anything at that point. In fact, when a sales person leaves, they and their accounts will probably be removed from this system.