How to delegate access ?

Hello,

I'm the IT guy and we do not have a computer provider anymore to manage our CRM (we're about to find a new one!). In the meantime, the sales department has asked me to create a user account that must be able to make an appointment for other sales representatives and access their customers (it is an external service provider who will act as a sales force).

As much as I know how to create a "classic" user account, I do not know how to do this type of operation.

Could anyone among you help me?

Thank you in advance!

Thierry