Changing Job Offer during Probation Period – BC

During the probation period as a sales rep with our company, the sales manager is feeling like the new hire is struggling to hit certain sales goals and may not be the right fit for the role they were hired for. However, the new hire has other skill sets that could be valuable for the company, and so the manager is now wanting to consider offering a slightly different role to which the new hire would be better suited. 
Is this change of job offer appropriate, and what would be the steps to ensure that both the employee and the company can maintain a good relationship throughout the process?