Short answer is there is no time period, so yes it will be fine to do what you are planning.
It is also good practice to change the drier/receiver, especially if it's old. But it isn't obligatory. Basically it's up to you, just get them to do the following:
I would ask whoever is emptying (reclaiming) the refrigerant to leave a couple of psi pressure in the system just in case (1 psig is fine).
At atmospheric pressure (zero gauge), the system is still 'full'. It's only when you go below atmospheric that you start to create a vacuum. As soon as you get any vacuum it wants to be filled by something; in this case air. Air contains a lot of water and water is the nemesis of a refrigeration circuit.
When you have done whatever you need to do, ask your garage (or 'fridge engineer) to pull a decent vacuum on the system, not just five minutes, to make sure you have expelled as much moisture as possible.
HTH