Hi @JulijaChemsi ,
It would be ok for you to obtain an EE SIM first, if you have not already done so. You can then try that out for a short number of days (e.g. 2 days to a week) to ensure everything works fine before requesting a PAC from your previous provider to port your number over.
Once your PAC is given to EE, your old contract will be cancelled and you will want to ensure you are ok with any early termination charges which may apply if you are still in a minimum term period with your previous provider. If you require more time to arrange the switch-over, you can request that your previous provider changes your old SIM to a Pay As You Go SIM at the end of the fixed term to minimize the overlap where you might be paying two service providers simultaneously.
Further guidance can be found at https://ee.co.uk/help/help-new/getting-started-and-upgrading/keep-my-number/how-do-i-transfer-my-num...
The Ofcom coverage checker can give you confidence if you want to provide your PAC to EE on day-one without trying out the service first. https://checker.ofcom.org.uk/en-gb/mobile-coverage
Good luck! 🤓
