Wiktionary
n. The act of moving a plant into a different pot. vb. (present participle of repot English)
WordNet
See repot
Wikipedia
Re-potting is the action of placing an already potted plant into a larger or smaller pot. A pot that fits a plant's root system better is normally used. Plants are usually re-potted according to the size of their root system. Most plants need to be re-potted every few years, because they become "pot-bound" or "root-bound." Plants' roots can sense its surroundings, including the size of the pot it is in, and increasing the pot size allows plant size to increase proportionally.
Usage examples of "repotting".
Terese who is repotting two little cacti merely puts her hands on her belly and weeps.
Her downstairs neighbour was repotting plants on the porch as they approached and looked up when they arrived.