Single permit while being on a different ID card

Dear All,


I have a question to which I cannot find an answer.  I have been working in Belgium since 2017 at an international organization, thus holding a Special ID Card (the P Card) issued by the Protocol Office of the Belgian MFA (this card is not the same as the one issued to diplomats).  My current contract expires on December 31, and recently I was offered a job here in Brussels, signed my contract and the employer already applied for a single permit.  While I am still trying how to seamlessly get off the P Card, I need to wait here in Belgium, as my kids are enrolled in a public school, and leaving somewhere in the middle of an academic year just to return at some point would be unwise.  Is there any way I can secure my stay here while waiting for the single permit after I surrender my Special Card?  I am not an EU national, but I have a passport that grants a visa waiver for 3 months (not sure if this can help).   Thank you!