According to Plato, can an object have multiple forms depending on its uses? For example, can a table have the form of tableness but also the form of chairness if people decide to use it as furniture to sit on?
In general, yes: sensible things partecipate to more than one form.
See Plato's Parmenides, 129a6–b6:
And even if all things come to take part in both, although these are opposites, and are themselves like and unlike themselves by participating in both, what is the wonder? If someone showed that the likes themselves become unlike, or the unlike like, this I should think was a marvel. But if he shows that those things that participate in both these appear to be affected by both—this seems nothing strange, not to me, Zeno; nor, for that matter, if someone shows that everything is one by participating in the one and those same things are many again by participating in plurality.
But it is not so clear that form=function for Plato.
And it is not so clear that everything can be "abstracted to forms"; see Plato's concern in 130b3–e4: "And about these too, Socrates, which would also seem ridiculous, such as hair and mud and dirt or any other most base and lowly thing: are you perplexed whether one must say that of each of these too there is a form apart, which is again other than the things we handle, or not? —In no way, said Socrates. Rather, those things we see such as they are; to think of a form of those would be exceedingly strange."
Amongst its other meanings, 'chair' can refer to 1) an object intended for the purpose of supporting the buttocks of a person wishing to take the weight off their feet, or 2) an object not normally consider a chair in the sense 1) but used for that purpose. A table is not a chair in the sense 1) but can be a chair in the sense 2). A table that has never been used as a chair might, depending upon its sturdiness, have the property of being usable as a chair. Once a table has been sat upon, it gains the property of having been used as a chair.
The broken bottle you mentioned in a comment is no longer a bottle in the sense of a small glass container. However, in English at least, it is common idiomatically to continue to use the same noun as a label to refer to an object even when its properties have changed to the point at which it can no longer fulfil the function which originally qualified it for the use of that label. For example, I might say that a my car was a write-off, using the words 'my car' to refer to a something that no longer functions as a car. So in one sense of the word, the broken bottle is no longer a bottle, and in another sense it is.