#include "bits/extc++.h"

using namespace std;

template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
    cerr << t;
    ((cerr << " | " << u), ...);
    cerr << endl;
}

#ifdef DEBUG
#define dbg(...)                                           \
    cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]" \
         << ": ";                                          \
    dbgh(__VA_ARGS__)
#else
#define cerr   \
    if (false) \
    cerr
#define dbg(...)
#endif

#define endl "\n"
#define long int64_t
#define sz(x) int(std::size(x))

void solve() {
    int n, m;
    cin >> n >> m;
    string arr[n];
    for (auto& a : arr) {
        cin >> a;
    }

    auto ibs = [&](int x, int y) -> bool {
        return 0 <= x && x < n && 0 <= y && y < m;
    };

    vector<pair<int, int>> q;
    auto push = [&](int x, int y) -> void {
        if (!ibs(x, y) || arr[x][y] != '?') {
            return;
        }

        for (int dx : {-1, 1}) {
            for (int dy : {-1, 1}) {
                if (!ibs(x + dx, y + dy)) {
                    continue;
                }

                char c1 = arr[x + dx][y + dy], c2 = arr[x + dx][y],
                     c3 = arr[x][y + dy];
                if (c1 == '?' || c2 == '?' || c3 == '?') {
                    continue;
                }
                if (c1 != c2 && c1 != c3) {
                    arr[x][y] = c2;
                    q.emplace_back(x, y);
                    return;
                }
            }
        }
    };

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            push(i, j);
        }
    }

    auto go_dfs = [&]() -> void {
        while (sz(q)) {
            auto [x, y] = q.back();
            q.pop_back();

            for (int dx : {-1, 0, 1}) {
                for (int dy : {-1, 0, 1}) {
                    push(x + dx, y + dy);
                }
            }
        }
    };

    go_dfs();
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (arr[i][j] == '?') {
                arr[i][j] = 'W';
                q.emplace_back(i, j);
                go_dfs();
            }
        }
    }

    for (int i = 0; i + 1 < n; i++) {
        for (int j = 0; j + 1 < m; j++) {
            char c1 = arr[i][j], c2 = arr[i + 1][j], c3 = arr[i][j + 1],
                 c4 = arr[i + 1][j + 1];
            if (c1 == c4 && c2 == c3 && c1 != c2) {
                cout << "NO" << endl;
                return;
            }
        }
    }
    cout << "YES" << endl;
    for (auto& a : arr) {
        for (auto& b : a) {
            cout << b;
        }
        cout << endl;
    }
}

int main() {
    cin.tie(nullptr);
    cin.exceptions(ios::failbit);
    ios_base::sync_with_stdio(false);
    int tcs;
    cin >> tcs;
    while (tcs--) {
        solve();
    }
}