I note Stephanos did not
actually say that not only is it advisable that the Community should be instructed beforehand [ if possible] but it would be a help if the Priest who would be Communing the infant was asked beforehand
As an EMHC I have been faced with a young Eastern Catholic child of about 4 for Communion - that morning I was giving Communion from the Ciborium. Fortunately the family concerned had been in the pew in front of me and I very quickly realsed that they were Eastern Catholic - it was a joy - one parent and 4 children - all very reverently paying attention - you can all guess the great give way of course. As the mum approached me with the wee one she pointed to the little one and I raised my eyebrows and she very quietly said 'She does Receive" . Now as an EMHC I am not permitted to refuse Communion to any who approach - I am supposed to see the Parish Priest [ Pastor] afterwards.This I forgot to do - but the family were talking to him after the end of Mass.
The next evening we had a Liturgy Group meeting and of course I had been seen and was challenged by the local know it all . I did of course defend my action quite vocally

and explain I had seen the children and parent in front of me during Mass - needless to say of course this lady did not know what ECs were [ now there's a surprise NOT ] The Pastor was not present so could not back me up.
I have seen this family again - but they all went to the Celebrant for Communion on each occasion.
Please , please take time to see the priest first so he does not get taken by surprise - not all Latin Priests will be comfortable in this situatiion