New subscription activating while abroad

Hi,

I transitioned my mobile contracts including two phone numbers to KPN. I have already recieved the SIM cards, and am now waiting for the transition to finalize. I unfortunately didn’t think about being abroad in Germany for holidays, and now the actual activation of the contract with KPN will happen while I am there.

I read here that this may be a problem. I think my situation is somewhat different as I already have the SIM cards. Does it help to “activate” them already (put them in a phone and unlock?), even if they won’t actually work. Are there any other ideas how to make sure that I don’t lose mobile connectivity completely?

Thank you!