Manufacturing site has to determine supporting functions performed by remote sites and document it.
Remote site has to be audited and scope of audit has to include supporting functions performed for manufacturing site. Remote site always has to be audited before manufacturing site. You have to be careful what you put in your scope of remote supporting functions, as your scope has to comply with scope of supporting functions audited at remote site.
There is no problem if scope of your remote site lists 5 functions and your scope lists 4, because meanwhile you had started to perform 1 function by yourself, as long remaining 4 supporting functions are same. Opposite situation - your scope lists 5 functions and scope of audited at remote site functions list 4 functions will result in issuing nonconformity.