reselect_nodes(.tokens)

tokens = tokens_spacy[tokens_spacy$doc_id == 'text4',]

## use a tquery to label the nodes that you want to manipulate
tq = tquery(relation = "relcl", label = "relative_clause")

## apply query to select nodes
tokens2 = select_nodes(tokens, tq) 

## reuses the tq, that is stored in tokens2
## this makes it easy to make the selection anew after a transformation
tokens2 = reselect_nodes(tokens2)